Re: Python Embedding Thread
Hi! Thank you very much for your answers. I have a menue with a script in it. So my app starts a new thread for each script. So I would like to run two scripts all the same time. Could someone give me a tip, what I have to set in my code? Thank you :) -- http://mail.python.org/mailman/listinfo/python-list
Re: string[i:j:k]
konstantin wrote: > > Thanks! > It seems that negative step leads in reverse direction. > But logic isn't completely clear for me. s = '123456789' s[::-2] > '97531' > > but s[:-1:-2] > '' > though I expected something like '8642' > What did i missed? > > -- You need to *start* at the second from last index: s[-2::-2] Regards, John -- http://mail.python.org/mailman/listinfo/python-list
Re: formatting list -> comma separated (slightly different)
On 9 Juli, 22:25, Michiel Overtoom <[EMAIL PROTECTED]> wrote:
> Paul & Robert wrote...
> > d = ["soep", "reeds", "ook"]
> >print ', '.join(d)
> > soep, reeds, ook
>
> I occasionally have a need for printing lists of items too, but in the form:
> "Butter, Cheese, Nuts and Bolts". The last separator is the word 'and'
> instead of the comma. The clearest I could come up with in Python is below.
> I wonder if there is a more pythonic solution for this problem. Maybe
> something recursive?
[snip]
> def pretty(f):
> if len(f)==0: return ''
> if len(f)==1: return f[0]
> sepwithcommas=f[:-1]
> sepwithand=f[-1]
> s=', '.join(sepwithcommas)
> if sepwithand:
> s+=' and '+sepwithand
> return s
def pretty(names):
return ' and '.join(', '.join(names).rsplit(', ', 1))
> friends=['Anne','Bob','Chris','Debbie','Eve','Fred']
print pretty(friends)
--
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Web Page Construction in Python
Dear Group, I am getting some questions on doing Web Pages in Python. I have some interactive codes in python for which I like to make web pages. I am trying to use kid. Kid I learnt, and is easy, too. My questions are: i) Am I going correct? ii) Is there any language other than kid? iii)The worked out examples of kid are not opening properly, is there any other URL where I can see them. iv) Can cgi scripting be done with kid? If any one can spend time on my questions. Best Regards, Subhabrata. -- http://mail.python.org/mailman/listinfo/python-list
Re: string[i:j:k]
konstantin wrote: On Jul 22, 9:18 am, alex23 <[EMAIL PROTECTED]> wrote: On Jul 22, 3:10 pm, konstantin <[EMAIL PROTECTED]> wrote: some_string[i:j:k] What does it mean? i = start position, j = end position, k = step size s = "ABABABABABABAB" s[0:6:2] 'AAA' s = "ABCABCABCABCABC" s[0:6:3] 'AA' Hope this helps. - alex23 Thanks! It seems that negative step leads in reverse direction. But logic isn't completely clear for me. s = '123456789' s[::-2] '97531' but s[:-1:-2] The slice s[:-1] means start at zero and go to n-1(where n-len(s)) (it does not mean start at zero and go to -1) So since the indexing is counting upward, the step size had better be positive. Thus: >>> s = '123456789' >>> s[:-1:2] '1357' >>> Gary Herron '' though I expected something like '8642' What did i missed? -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: tail-rec decorator, well still blows the stack...
thanks i already have perfect iterative versions of fibonacci. def fib(n): a, b = 1, 0 while n: a, b, n = b, a+b, n-1 return b I know the example is not the way to write pythonic code, I was just learning about decorators and then I saw this example and tried it out. but thanks now i understand why it didn't work. -- http://mail.python.org/mailman/listinfo/python-list
Re: string[i:j:k]
On Jul 22, 9:18 am, alex23 <[EMAIL PROTECTED]> wrote: > On Jul 22, 3:10 pm, konstantin <[EMAIL PROTECTED]> wrote: > > > some_string[i:j:k] > > What does it mean? > > i = start position, j = end position, k = step size > > >>> s = "ABABABABABABAB" > >>> s[0:6:2] > 'AAA' > >>> s = "ABCABCABCABCABC" > >>> s[0:6:3] > > 'AA' > > Hope this helps. > > - alex23 Thanks! It seems that negative step leads in reverse direction. But logic isn't completely clear for me. >>> s = '123456789' >>> s[::-2] '97531' but >>> s[:-1:-2] '' though I expected something like '8642' What did i missed? -- http://mail.python.org/mailman/listinfo/python-list
Re: proliferation of computer languages
I can't say that I see any particular point to the essay. But I did want to point out that Oz should not be considered part of the ML family. Aside from not being statically typed - a very central tenet to ML, Oz is much more part of the Logic family of languages (Mercury, Prolog, etc...). On Jul 18, 12:17 pm, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > Today, i took sometime to list some major or talked-about langs that > arose in recent years. > > ML Family: > > * Oz�J. Concurrent. Multiparadigm. > * Alice�J. Concurrent, ML derivative. Saarland University, Germany. > * OCaml�J > * F#�J. Microsoft's functional lang. -- http://mail.python.org/mailman/listinfo/python-list
Re: Time Complexity of String Operations
youtoo wrote: It has been extensively discussed the time complexity (quadratic) of string concatenation (due to string's immutability). But what is: == the time complexity of string indexing? Is it constant? == the time complexity of string slicing? Is it O(K) with K the slice's length? How are strings stored in Python? As arrays? As linked lists? There is a Py wiki page on such issues. A wiki search should find it. -- http://mail.python.org/mailman/listinfo/python-list
Re: tail-rec decorator, well still blows the stack...
ssecorp wrote: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/496691 so I try it and when I run: @Decorators.tail_recursion def fibtr(n): def fibt(a, b, n): if n <= 1: return b else: return fibt(b, a + b, n - 1) if n == 0: return 0 else: return fibt(0, 1, n); it still blows the stack. so what is the point? is it impossible to get "real" tail-recursion in Python? As you have used it, the decorator wraps the *outer* non-recursive function which is just called once anyway. Useless. Try wrapping fibt instead. That said, this recipe significantly increases the running time by multiplying the number of function calls by about three. I do not regard it as removing the recursion, but, rather, as making it indirect (via two other calls) so as to remove the unneeded stack frames (and the space problem) in between recursive calls. Much simpler is the trivial rewrite with while to do 'in frame recursion', or iteration. This also removes the need for outer and inner function. rearrange fibt as def fibt(a,b,n): if n > 1: return fibt(b, a+b, n-1) else: return b and rewrite as def fibi(a,b,n): while n > 1: a,b,n = b,a+b,n-1 return b by directly binding the new arguments to the parameters. Move the initialization inside the function (and delete the outer wrapper) to get def fib(n): if n==0: return 0 else: a,b = 0,1 while n > 1: a,b,n = b,a+b,n-1 return b and even turn the induction back a step and simplify to def fib(n): a,b = 1,0 while n: a,b,n = b,a+b,n-1 return b Why do some people fight writing efficient beautiful code like this that works with Python's design to instead write less efficient and uglier code that works against Python's design? If you do not want function calls (and runtime name resolution), do not write them! Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: string[i:j:k]
On Jul 22, 3:10 pm, konstantin <[EMAIL PROTECTED]> wrote: > some_string[i:j:k] > What does it mean? i = start position, j = end position, k = step size >>> s = "ABABABABABABAB" >>> s[0:6:2] 'AAA' >>> s = "ABCABCABCABCABC" >>> s[0:6:3] 'AA' Hope this helps. - alex23 -- http://mail.python.org/mailman/listinfo/python-list
string[i:j:k]
Hello, I'm not a newbie in python, but recently faced a problem in simple expression: some_string[i:j:k] What does it mean? I believe this grammar (http://docs.python.org/ref/ slicings.html) describes the syntax. But I can't grasp it. Thanks! -- http://mail.python.org/mailman/listinfo/python-list
Re: Website Creation using Python
On Jul 22, 12:44 am, Amie <[EMAIL PROTECTED]> wrote: > I would like some help on how to create a website using the python > programming language. > I've tried using enamel, but had some problems because I could not > create html tables and intergrating it with python, like you use it > when coding in php. If you're familiar with the PHP approach and are planning on using Apache, you might find mod_python and Python Server Pages more accessible: * http://en.wikipedia.org/wiki/Mod_python * http://www.onlamp.com/pub/a/python/2004/02/26/python_server_pages.html There are a *lot* of web frameworks for Python (I hadn't even heard of Enamel prior to your post) which provide varying degrees of support and ease of use, there's a nice overview here: * http://wiki.python.org/moin/WebFrameworks Django does seem to be leading in terms of popularity atm. Having developed an application in TurboGears, I can testify that having a large user base to draw support help from can be -very- handy. Hope this helps. - alex23 -- http://mail.python.org/mailman/listinfo/python-list
Re: scanf in python
Robert Kern a écrit : AMD wrote: Hello, I often need to parse strings which contain a mix of characters, integers and floats, the C-language scanf function is very practical for this purpose. I've been looking for such a feature and I have been quite surprised to find that it has been discussed as far back as 2001 but never implemented. The second Google hit is a pure Python implementation of scanf. http://hkn.eecs.berkeley.edu/~dyoo/python/scanf/ Hi Robert, I had seen this pure python implementation, but it is not as fast or as elegant as would be an implementation written in C directly within python with no need for import. Cheers, André -- http://mail.python.org/mailman/listinfo/python-list
Re: Time Complexity of String Operations
On Mon, Jul 21, 2008 at 10:31 PM, youtoo <[EMAIL PROTECTED]> wrote: > It has been extensively discussed the time complexity (quadratic) of > string concatenation (due to string's immutability). Actually, it is roughly linear, at least for reasonable string lengths: $ python -V Python 2.5.2 $ python -mtimeit -s "n=1000; a='#'*n" "a+a" 100 loops, best of 3: 1 usec per loop $ python -mtimeit -s "n=1; a='#'*n" "a+a" 10 loops, best of 3: 5.88 usec per loop $ python -mtimeit -s "n=10; a='#'*n" "a+a" 1 loops, best of 3: 59.8 usec per loop Repeatedly constructing a string by appending a constant number of characters at a time, however, is quadratic in the final string length (although VM optimizations may affect this). > But what is: > > == the time complexity of string indexing? Is it constant? Yes. > == the time complexity of string slicing? Is it O(K) with K the > slice's length? I suspect so, since the time is dominated by the time taken to copy the data into a new string object. > How are strings stored in Python? As arrays? As linked lists? Arrays; see Include/stringobject.h in the Python source distribution. -- David -- http://mail.python.org/mailman/listinfo/python-list
fromfile error on windows, not mac
Hello,
I am using the numpy fromfile function to read binary data from a file
on disk. The problem is that the program runs fine on a Mac, but gives
an error or warning on windows when trying to read the data. I use it
like this:
Signal = zeros((N, 16), dtype=float32)
for sample in range(0, N):
# this function gets the next position in the file to seek to
s = getFilePos(sample)
# go to the correct location in the file; this IS checked to make
sure it is within the file
mFile.seek(s)
# read the 16 float32 values from the file
D = fromfile(mFile, dtype=numpy.float32, 16)
# save D in Signal
Signal[sample, :] = D
This will fail when sample is ~4. If I change the range to (5,N),
skipping the "bad" file location, it will run fine for a few samples,
and then give another error. The message it gives is:
"16 items requested but only 7 read"
So D is a 7x1 vector, and the program dies when it tries to assign D
to the slice of Signal ("ValueError: shape mismatch: objects cannot be
broadcast to a single shape").
On windows, the Python version is 2.5.2, and the most recent numpy and
scipy are being used as well. I tried using Enthought, but it gave
this error as well, in addition to a c runtime error whenever I
imported scipy (which is another post topic...).
Any ideas on what might be causing this? Is there a way to debug the
fromfile function? And, remember, this works perfectly on a Mac. Would
compiling everything (python, scipy, numpy) potentially solve this?
Thanks!
--
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Re: Python Embedding Thread
"Benjamin" <[EMAIL PROTECTED]> wrote: > Two threads should not be running through the Python VM concurrently > in the same process. The GIL has to be held *any* time you use the > Python API. When you want to release the GIL (to process something in > C), use PY_BEGIN_ALLOW_THREADS and > PY_END_ALLOW_THREADS around the > places where threads can run. I think he is trying to call python from thread, according to the documentation: "Beginning with version 2.3, threads can now take advantage of the PyGILState_*() functions to do all of the above automatically." - http://docs.python.org/api/threads.html I use it everywhere on my multithreaded server without problem. Salam, -Jaimy -- http://mail.python.org/mailman/listinfo/python-list
Re: tail-rec decorator, well still blows the stack...
On Mon, Jul 21, 2008 at 10:01 PM, ssecorp <[EMAIL PROTECTED]> wrote: > http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/496691 > > so I try it and when I run: > @Decorators.tail_recursion > def fibtr(n): >def fibt(a, b, n): >if n <= 1: >return b >else: >return fibt(b, a + b, n - 1) >if n == 0: >return 0 >else: >return fibt(0, 1, n); > > it still blows the stack. so what is the point? is it impossible to > get "real" tail-recursion in Python? Python does not perform tail-call elimination, and there are currently no plans to make it do so. See http://mail.python.org/pipermail/python-dev/2004-July/046171.html and the ensuing discussion for an explanation. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
Grant Edwards wrote: On 2008-07-22, Larry Bates <[EMAIL PROTECTED]> wrote: You talk about "writing it in assembly language for each MPU chip". Actually it is even better than that. We now have these modern inventions, called compilers that do that type of work for us. They translate high level instructions, not into assembler but into machine language. Actually, all of the compilers I'm familiar with (gcc and a handful of cross compilers for various microprocessors) translate from high-level languages (e.g. C, C++) into assembly, which is then assembled into relocatable object files, which are then linked/loaded to produce machine language. I just learned something I did not know. I was under the impression that they translated directly to machine code without ever actually generating Assembler text files. Seems like a waste to generate the text and turn around run that through the assembler, but what do I know. I guess that way the compiler can have pluggable assembler back-ends. -Larry -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with Python Server Pages (PSP)
On Jul 22, 5:18 am, Graham Dumpleton <[EMAIL PROTECTED]> wrote: > On Jul 21, 9:42 pm, [EMAIL PROTECTED] wrote: > > > > > > > Hi, > > > I am facing a very basic problem with PSP. I have installedmod_python > > (in fedora Core 1), added the lines required for loading Python > > modules and handling PSP pages. I have created a hello.psp page. But > > when I try to view this hello.psp page, all Python code are getting > > displayed. > > > The said page is stored at /var/www/html/psp/hello.psp. I guess this > > is some configuration problem with Apache, but not able to figure out > > the exact problem. I have tried putting those configuration lines for > > psp in both httpd.conf and python.conf files. But still it is not > > working. > > > The Python module (mod_python) is getting loaded. Because when I > > telnet to my server, I can find that in the headers. > > > These are the versions of the softwares: > > Apache: 2.0.47 > > Python: 2.2.3mod_python: 3.0.3 > > > Thnaks for all your suggestions. > > What is the Apache configuration snippet you are using to enable > mod_python and PSP file handling? > > Graham- Hide quoted text - > > - Show quoted text - Hi Graham, The configuration used in httpd.conf file looks like: AddHandler .psp .psp_ PythonHandler modules/python PythonDebug On -- http://mail.python.org/mailman/listinfo/python-list
Re: Website Creation using Python
Amie wrote: Afternoon, I would like some help on how to create a website using the python programming language. I've tried using enamel, but had some problems because I could not create html tables and intergrating it with python, like you use it when coding in php. Any help would be appreciated. Thanks Python is not PHP. Page generation is done differently. You might take a look at Django's web framework: http://www.djangoproject.com/ or http://pylonshq.com/ WARNING - Python web frameworks are MUCH more powerful than just using PHP to place some dynamic content on a web page. For many people, PHP will still be an easy to implement solution if your project isn't very complex. As the complexity grows, the need for additional power and flexibility grows also. -Larry -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On 2008-07-22, Larry Bates <[EMAIL PROTECTED]> wrote: > You talk about "writing it in assembly language for each MPU > chip". Actually it is even better than that. We now have > these modern inventions, called compilers that do that type of > work for us. They translate high level instructions, not > into assembler but into machine language. Actually, all of the compilers I'm familiar with (gcc and a handful of cross compilers for various microprocessors) translate from high-level languages (e.g. C, C++) into assembly, which is then assembled into relocatable object files, which are then linked/loaded to produce machine language. -- Grant Edwards grante Yow! "DARK SHADOWS" at is on!! Hey, I think visi.comthe VAMPIRE forgot his UMBRELLA!! -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
[EMAIL PROTECTED] wrote: I'm just learning about Python now and it sounds interesting. But I just read (on the Wiki page) that mainstream Python was written in C. That's what I was searching for: Python was written in what other language? See, my concern was something like: OK, if Python is so hot, then, hopefully someone is writing it in assembly language for each MPU chip out there. Otherwise, if, say, they've written it in C#, then it looks like the REAL, generally useful language to learn is C# and Python is akin to Visual Basic or something: a specialty languagewhereas REAL WORLD programmers who want to be generally useful go and learn C#. So I was suspecting the Python compiler or interpreter is written in a REAL language like C#. So, Wiki says it's written in C! It's almost as if it were an intentional trick...write your own, new language in an OLD, real world language that is passe. Compile it into executable modules of course, so it is a real, working compiler, alright. But the SOURCE is some old, high level language which no one wants to use anymore! So now you've got a hot new language package and no one can say "well, it is written in, the SOURCE code is written in, a REAL language." No, it's not! The source is some outdated language and compiler and no one is going to prefer learning THAT to learning your hot new language! I'm not dissing Python, here. Just noting that, if it is written in C, that throws a curve at me in trying to balance the value of learning Python vs. some other major language. SPSS (was and may still be) written in Fortran and the Fortran compiler was written in C. But NOBODY would suggest that you try to solve the problems that SPSS is used for in C. You talk about "writing it in assembly language for each MPU chip". Actually it is even better than that. We now have these modern inventions, called compilers that do that type of work for us. They translate high level instructions, not into assembler but into machine language. -Larry -- http://mail.python.org/mailman/listinfo/python-list
Time Complexity of String Operations
It has been extensively discussed the time complexity (quadratic) of string concatenation (due to string's immutability). But what is: == the time complexity of string indexing? Is it constant? == the time complexity of string slicing? Is it O(K) with K the slice's length? How are strings stored in Python? As arrays? As linked lists? Thanks a lot! yt. -- http://mail.python.org/mailman/listinfo/python-list
Re: tail-rec decorator, well still blows the stack...
I my function not proper tail-recursion? because this doesn't blow the stack: #!/usr/bin/env python2.4 # This program shows off a python decorator( # which implements tail call optimization. It # does this by throwing an exception if it is # it's own grandparent, and catching such # exceptions to recall the stack. import sys class TailRecurseException: def __init__(self, args, kwargs): self.args = args self.kwargs = kwargs def tail_call_optimized(g): """ This function decorates a function with tail call optimization. It does this by throwing an exception if it is it's own grandparent, and catching such exceptions to fake the tail call optimization. This function fails if the decorated function recurses in a non-tail context. """ def func(*args, **kwargs): f = sys._getframe() if f.f_back and f.f_back.f_back \ and f.f_back.f_back.f_code == f.f_code: raise TailRecurseException(args, kwargs) else: while 1: try: return g(*args, **kwargs) except TailRecurseException, e: args = e.args kwargs = e.kwargs func.__doc__ = g.__doc__ return func @tail_call_optimized def factorial(n, acc=1): "calculate a factorial" if n == 0: return acc return factorial(n-1, n*acc) print factorial(1) # prints a big, big number, # but doesn't hit the recursion limit. @tail_call_optimized def fib(i, current = 0, next = 1): if i == 0: return current else: return fib(i - 1, next, current + next) print fib(1) # also prints a big number, # but doesn't hit the recursion limit. -- http://mail.python.org/mailman/listinfo/python-list
tail-rec decorator, well still blows the stack...
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/496691 so I try it and when I run: @Decorators.tail_recursion def fibtr(n): def fibt(a, b, n): if n <= 1: return b else: return fibt(b, a + b, n - 1) if n == 0: return 0 else: return fibt(0, 1, n); it still blows the stack. so what is the point? is it impossible to get "real" tail-recursion in Python? -- http://mail.python.org/mailman/listinfo/python-list
Re: How to install simplejson on WinXP
I just installed again to see the error message. But it worked OK now. The problem was about compiling the c extension last time. Fredrik Lundh wrote: > lookon wrote: > > > I am new to python and had difficulty in installing simplejson on > > WinXP...Could anyone help me? Thanks > > what did you try, and what happened when you tried that? > > -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Embedding Thread
On Jul 21, 6:56 am, [EMAIL PROTECTED] wrote:
> Hi :)
>
> I want to run Python in my app. That works still fine. But my app
> supports now Threads and I would like to know what to do, that it runs
> without problems.
>
> PyGILState_Release and PyGILState_Ensure should solve the problem
> right? Where do I have to put this two commands around? between each
> Command that increase, decrease a reference?
Two threads should not be running through the Python VM concurrently
in the same process. The GIL has to be held *any* time you use the
Python API. When you want to release the GIL (to process something in
C), use PY_BEGIN_ALLOW_THREADS and PY_END_ALLOW_THREADS around the
places where threads can run.
>
> Currently, this is a small code-snippet that represents the part of
> the code-execution:
>
> PyObject *f_globals=NULL, *f_locals=NULL,
> *mod=NULL, *rv=NULL;
>
> mod = PyImport_ImportModule("__main__");
> if (!mod)
> return;
>
> f_globals = PyModule_GetDict(mod);
> f_locals = PyDict_New();
> PyDict_Update(f_locals, f_globals);
> if (!f_locals) {
> Py_DECREF(mod);
> PyErr_Print();
> return;
> }
>
> rv = PyRun_String( ,
> Py_file_input, f_locals,
> f_locals);
> if (!rv)
> PyErr_Print();
>
> Py_XDECREF(rv);
> Py_DECREF(mod);
> Py_DECREF(f_locals);
> Py_DECREF(f_locals);
>
> Thanks a lot for your help :)
--
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Re: Odd math related issue.
On Jul 21, 3:52 am, Fredrik Lundh <[EMAIL PROTECTED]> wrote: > Robert Rawlins wrote: > > I’ve got what seems to me to be a totally illogical math issue here > > which I can’t figure out. Take a look at the following code: > > > /self/.__logger.info(/"%i / %i"/ % (bytes_transferred, > > /self/.__sessions[path].total_bytes)) > > > percentage = bytes_transferred / > > /self/.__sessions[path].total_bytes * 100 > > > /self/.__logger.info(/"%i"/ % percentage) > > > Seems fairly straight forward, you would think. It takes two values and > > calculates the percentage of one from the other, however, percentage > > always comes back as ‘0’ for some reason, look at this log output. > > if you divide two integers, you'll get an integer back (in Python 2.X, > at least). quick fix: > > percentage = bytes_transferred * 100 / total_bytes > > The most wonderful statement in the Python language is from __future__ import division -- http://mail.python.org/mailman/listinfo/python-list
Re: Pinging a machine from python
On May 26, 5:21 am, Zerge <[EMAIL PROTECTED]> wrote: > On May 25, 11:13 am, Prasanth <[EMAIL PROTECTED]> wrote: > > > I tried pinging a machine from python using socket programming but > > could not do it. Is there any module which we can use to ping the > > machine < like net::ping in perl> or can you give me simple program. > > Import OS > ip=192.168.1.1 > pingtext="ping "+ip+" -n 1" > pingresult=os.popen(pingtext).readlines() > > "OS" gives you access to the command line of the operating system. Thanks for the solution guys. But the above program is giving the output as : If we print pingresult it is giving the output as : ['\r\n', 'Pinging 0.168.1.1 with 32 bytes of data:\r\n', '\r\n', 'Request timed out.\r\n', '\r\n', 'Ping statistics for 0.168.1.1:\r \n', 'Packets: Sent = 1, Received = 0, Lost = 1 (100% loss),\r\n'] my requirement is IP address and whether the machine is pinging or not. we should not display the above output. However we can do it by using regular expression or there is any other way. Please suggest. Thanks, Prasanth. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Jul 20, 6:50 pm, [EMAIL PROTECTED] wrote: > So I was suspecting the Python compiler or interpreter is written in a > REAL language like C#. So, Wiki says it's written in C! It's almost as > if it were an intentional trick...write your own, new language in an > OLD, real world language that is passe. Compile it into executable > modules of course, so it is a real, working compiler, alright. But the > SOURCE is some old, high level language which no one wants to use > anymore! So now you've got a hot new language package and no one can > say "well, it is written in, the SOURCE code is written in, a REAL > language." No, it's not! The source is some outdated language and > compiler and no one is going to prefer learning THAT to learning your > hot new language! Young people these days... I will just answer using one of old Microsoft's ads: "My compiler compiled yours." -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
it's clear to me that the perfect language should exist a priori, coming to being causa sui. Having to actually implement a language is disgusting and unnatural. -- http://mail.python.org/mailman/listinfo/python-list
RE: Python Written in C?
Fredrik Lundh wrote: > rynt wrote: > >> You're either --- >> A. A Troll >> B. A young, immature programmer trying to show off or >> C. A total idiot. > > you forgot the "All of the above" choice. I read it as an inclusive "or". Tim Delaney -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Jul 20, 9:18 pm, Michiel Overtoom <[EMAIL PROTECTED]> wrote: . > > Many major text/word processing programs (Emacs, vi, MS-Word) are also > written in C. Does that mean you should do all your text processing in C? Well, actually, as a COBOL geezer I should not complain about Python. Rumor had it that the COMPUTE statement in COBOL invoked FORTRAN arithmetic modules. Yes, real programmers DO write in FORTRAN! Frankly, I say screw not only object-oriented programming but structured programming as well. I think someone should write a compiler, "Revenge of BASIC." It would have good old REMs, FOR...TO...NEXTs, GOSUBS, GOTOs, etc. Standard libraries of subroutines, and/or Copy Libraries of source code, could handle switching to new screens or forms, placement of objects, alteration of characteristics of all these, detection of mouse and keyboard actions, graphics, sound, placement of HTML code, EVERYTHING! If anyone wants to write this compiler, they should probably do it in Python. Make it open source, of course. I'm waiting! -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with Python Server Pages (PSP)
On Jul 21, 9:42 pm, [EMAIL PROTECTED] wrote: > Hi, > > I am facing a very basic problem with PSP. I have installedmod_python > (in fedora Core 1), added the lines required for loading Python > modules and handling PSP pages. I have created a hello.psp page. But > when I try to view this hello.psp page, all Python code are getting > displayed. > > The said page is stored at /var/www/html/psp/hello.psp. I guess this > is some configuration problem with Apache, but not able to figure out > the exact problem. I have tried putting those configuration lines for > psp in both httpd.conf and python.conf files. But still it is not > working. > > The Python module (mod_python) is getting loaded. Because when I > telnet to my server, I can find that in the headers. > > These are the versions of the softwares: > Apache: 2.0.47 > Python: 2.2.3mod_python: 3.0.3 > > Thnaks for all your suggestions. What is the Apache configuration snippet you are using to enable mod_python and PSP file handling? Graham -- http://mail.python.org/mailman/listinfo/python-list
Re: Error importing modules with mod_python
On Jul 22, 3:30 am, Aaron Scott <[EMAIL PROTECTED]> wrote: > I've installedmod_python, and everything seems to be working, but it > fails when I try to import another file into the file that's actually > producing the output. I have these lines at the top of index.py: > > frommod_pythonimport apache > from storylab import * > > ... and in the directory where index.py resides (/htdocs/python/), I > have a directory called "storylab". Inside that directory is > __init__.py. When I try to execute /htdocs/python/index.py, I get the > following error: > > --- > > MOD_PYTHONERROR > ProcessId: 828 > Interpreter: 'localhost' > ServerName: 'localhost' > DocumentRoot: 'C:/htdocs' > URI: '/python/index.py' > Location: None > Directory: 'C:/htdocs/python/' > Filename: 'C:/htdocs/python/index.py' > PathInfo: '' > Phase: 'PythonHandler' > Handler: 'index' > > Traceback (most recent call last): > > File "C:\Python25\lib\site-packages\mod_python\importer.py", line > 1537, in HandlerDispatch > default=default_handler, arg=req, silent=hlist.silent) > > File "C:\Python25\lib\site-packages\mod_python\importer.py", line > 1202, in _process_target > module = import_module(module_name, path=path) > > File "C:\Python25\lib\site-packages\mod_python\importer.py", line > 296, in import_module > log, import_path) > > File "C:\Python25\lib\site-packages\mod_python\importer.py", line > 680, in import_module > execfile(file, module.__dict__) > > File "C:\htdocs\python\index.py", line 2, in > from storylab import * > > ImportError: No module named storylab > > --- > > What am I doing wrong? Any insight would be greatly appreciated. You can't put Python packages in same directory as handler scripts managed by mod_python. See documentation for import_module() in: http://www.modpython.org/live/current/doc-html/pyapi-apmeth.html Graham -- http://mail.python.org/mailman/listinfo/python-list
Re: scanf in python
AMD wrote: Hello, I often need to parse strings which contain a mix of characters, integers and floats, the C-language scanf function is very practical for this purpose. I've been looking for such a feature and I have been quite surprised to find that it has been discussed as far back as 2001 but never implemented. The second Google hit is a pure Python implementation of scanf. http://hkn.eecs.berkeley.edu/~dyoo/python/scanf/ -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Converting List of String to Integer
Samir wrote: For my small list, I didn't notice a discernible increase in speed, but I may have to try it with a larger list size. About speed, and memory consumption: List comprehensions (http://docs.python.org/tut/node7.html#SECTION00714) are just shortcuts for for-loops. I do not believe there is any speed benefit. However, there are generators, they basically load one part of an iterator (a list in this case) at a time, this can greatly reduce memory usage. Have a look at PEP 289: http://www.python.org/dev/peps/pep-0289/ Here is the list comprehension as a generator (actually 2): n = ((int(i) for i in k) for k in a) Note, you can't just print a generator, it only computes something when needed: >>> print n You can, however iterate over it: In [2]: for k in n: : for i in k: : print i, : : 1 2 3 4 5 6 7 8 9 0 In [3]: n = ((int(i) for i in k) for k in a) In [49]: list(n) Out[49]: [, , , ] Each sub-list is a generator too! In [50]: n = ((int(i) for i in k) for k in a) In [51]: for i in list(n): # list() converts the variable n to a list : list(i) : : Out[51]: [1, 2] Out[51]: [3] Out[51]: [4, 5, 6] Out[51]: [7, 8, 9, 0] This is only going to make a difference if you were dealing with a *very* large data set. I thought I would show you even if you never user them, for learning purposes. Note: a generator is one way, redefine it every time you use it. -- Andrew -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Mon, Jul 21, 2008 at 3:53 PM, DaveM <[EMAIL PROTECTED]> wrote: > On Mon, 21 Jul 2008 03:18:01 +0200, Michiel Overtoom <[EMAIL PROTECTED]> > wrote: > > > >Many major text/word processing programs (Emacs, vi, MS-Word) are also > >written in C. > > I thought Emacs was written in Lisp. Large parts of Emacs are indeed implemented in Emacs Lisp. There's are some core functions implemented in C. MS-Word, afaik, had very substantial parts written in Visual Basic. Tom > DaveM > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
[EMAIL PROTECTED] writes: > I'm just learning about Python now and it sounds interesting. But I > just read (on the Wiki page) that mainstream Python was written in C. > That's what I was searching for: Python was written in what other > language? Well, yes, the interpreter and a handful of the core modules are written in C. However, most of Python -- especially the cool bits -- aren't written in C. They're written in ... Python! -- Teiresias -- http://mail.python.org/mailman/listinfo/python-list
Re: Converting List of String to Integer
Samir wrote:
On Jul 21, 6:15 pm, Andrew Freeman <[EMAIL PROTECTED]> wrote:
Samir wrote:
On Jul 21, 3:20 pm, Gary Herron <[EMAIL PROTECTED]> wrote:
Samir wrote:
Hi Everyone,
I am relatively new to Python so please forgive me for what seems like
a basic question.
Assume that I have a list, a, composed of nested lists with string
representations of integers, such that
a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
I would like to convert this to a similar list, b, where the values
are represented by integers, such as
b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
I have unsuccessfully tried the following code:
n = []
for k in a:
n.append([int(v) for v in k])
print n
Does anyone know what I am doing wrong?
Thanks in advance.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
You didn't tell us how it failed for you, so I can't guess what's wrong.
However, your code works for me:
>>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
>>> n = []
>>> for k in a:
...n.append([int(v) for v in k])
...
>>> print n
[[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
(Although you seem to have confused variables b and n.)
Gary Herron- Hide quoted text -
- Show quoted text -
Hi Gary,
Thanks for your quick response (and sorry about mixing up b and n).
For some reason, the logic I posted seems to work ok while I'm using
the Python shell, but when used in my code, the program just hangs.
It never outputs the results. Below is the code in its entirety. Is
there a problem with my indendentation?
a = n = []
t = """
1 2
3
4 5 6
7 8 9 0
"""
d = t.split("\n")
for x in range(1,len(d)-1):
a.append(d[x].split(" "))
print a
for k in a:
n.append([int(v) for v in k])
print n
Thanks again.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
I think this will work better, a sub-list comprehension of sorts:
n = [[int(i) for i in k] for k in a]
here is an ipython interactive session using it:
In [1]: a = n = []
In [2]: t = """
...: 1 2
...: 3
...: 4 5 6
...: 7 8 9 0
...: """
In [3]:
In [4]: d = t.split("\n")
In [5]: for x in range(1,len(d)-1):
...: a.append(d[x].split(" "))
...:
...:
In [6]: a
Out[6]: [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
In [7]: n = [[int(i) for i in k] for k in a]
In [8]: n
Out[8]: [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
--
Andrew- Hide quoted text -
- Show quoted text -
Andrew,
Thanks for the tip, though the syntax makes my head spin a bit in
trying to comprehend it. For my small list, I didn't notice a
discernible increase in speed, but I may have to try it with a larger
list size.
Incidentally, I had never heard of iPython but from their web site, it
looks like an interesting tool. I'll have to check it out.
Thanks.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
If it helps look at this:
n = [[int(i) for i in k] for k in a]
like this:
n = []
for k in a:
for i in k:
n.append(int(i))
It is more verbose and easier to read and they both do exactly the same
thing!
iPython is great, to install it you might try easy_install:
http://peak.telecommunity.com/DevCenter/EasyInstall
Then in a command line type:
easy_install ipython
Then, once it is complete, to use iPython type:
ipython
--
Andrew
--
http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Jul 21, 8:26 am, Johannes Bauer <[EMAIL PROTECTED]> wrote: > Mensanator schrieb: > > > You want cool? > > THIS is cool: > > > j = ((invert(xyz[1]-xyz[0],xyz[1]**(k-1))*(xyz[1]**(k-1)-prev_gen[2])) > > % xyz[1]**(k-1))/xyz[1]**(k-2) > > You call it cool, I call it NameError: name 'invert' is not defined. It is when you do: from gmpy import * That single line wasn't the whole program. What's cool is that it IS a single line, that does answers with >5 decimal digits without breaking a sweat. Sure, you can use GMP with C (and I've done it). But it's nothing like doing it in Python. > > Regards, > Johannes > > -- > "Wer etwas kritisiert muss es noch lange nicht selber besser können. Es > reicht zu wissen, daß andere es besser können und andere es auch > besser machen um einen Vergleich zu bringen." - Wolfgang Gerber > in de.sci.electronics <[EMAIL PROTECTED]> -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Mon, 21 Jul 2008 03:18:01 +0200, Michiel Overtoom <[EMAIL PROTECTED]> wrote: >Many major text/word processing programs (Emacs, vi, MS-Word) are also >written in C. I thought Emacs was written in Lisp. DaveM -- http://mail.python.org/mailman/listinfo/python-list
Re: Converting List of String to Integer
On Jul 21, 6:15 pm, Andrew Freeman <[EMAIL PROTECTED]> wrote:
> Samir wrote:
> > On Jul 21, 3:20 pm, Gary Herron <[EMAIL PROTECTED]> wrote:
>
> >> Samir wrote:
>
> >>> Hi Everyone,
>
> >>> I am relatively new to Python so please forgive me for what seems like
> >>> a basic question.
>
> >>> Assume that I have a list, a, composed of nested lists with string
> >>> representations of integers, such that
>
> >>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
>
> >>> I would like to convert this to a similar list, b, where the values
> >>> are represented by integers, such as
>
> >>> b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
>
> >>> I have unsuccessfully tried the following code:
>
> >>> n = []
> >>> for k in a:
> >>> n.append([int(v) for v in k])
> >>> print n
>
> >>> Does anyone know what I am doing wrong?
>
> >>> Thanks in advance.
>
> >>> Samir
> >>> --
> >>>http://mail.python.org/mailman/listinfo/python-list
>
> >> You didn't tell us how it failed for you, so I can't guess what's wrong.
>
> >> However, your code works for me:
>
> >> >>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
> >> >>> n = []
> >> >>> for k in a:
> >> ... n.append([int(v) for v in k])
> >> ...
> >> >>> print n
> >> [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
>
> >> (Although you seem to have confused variables b and n.)
>
> >> Gary Herron- Hide quoted text -
>
> >> - Show quoted text -
>
> > Hi Gary,
>
> > Thanks for your quick response (and sorry about mixing up b and n).
> > For some reason, the logic I posted seems to work ok while I'm using
> > the Python shell, but when used in my code, the program just hangs.
> > It never outputs the results. Below is the code in its entirety. Is
> > there a problem with my indendentation?
>
> > a = n = []
> > t = """
> > 1 2
> > 3
> > 4 5 6
> > 7 8 9 0
> > """
>
> > d = t.split("\n")
>
> > for x in range(1,len(d)-1):
> > a.append(d[x].split(" "))
> > print a
>
> > for k in a:
> > n.append([int(v) for v in k])
>
> > print n
>
> > Thanks again.
>
> > Samir
> > --
> >http://mail.python.org/mailman/listinfo/python-list
>
> I think this will work better, a sub-list comprehension of sorts:
> n = [[int(i) for i in k] for k in a]
>
> here is an ipython interactive session using it:
> In [1]: a = n = []
>
> In [2]: t = """
> ...: 1 2
> ...: 3
> ...: 4 5 6
> ...: 7 8 9 0
> ...: """
>
> In [3]:
>
> In [4]: d = t.split("\n")
>
> In [5]: for x in range(1,len(d)-1):
> ...: a.append(d[x].split(" "))
> ...:
> ...:
>
> In [6]: a
> Out[6]: [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
>
> In [7]: n = [[int(i) for i in k] for k in a]
>
> In [8]: n
> Out[8]: [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
> --
> Andrew- Hide quoted text -
>
> - Show quoted text -
Andrew,
Thanks for the tip, though the syntax makes my head spin a bit in
trying to comprehend it. For my small list, I didn't notice a
discernible increase in speed, but I may have to try it with a larger
list size.
Incidentally, I had never heard of iPython but from their web site, it
looks like an interesting tool. I'll have to check it out.
Thanks.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
Getting clear error messages with a Python templating system?
Hi there,
I'm developing web applications in Python, so I use a templating system to
produce HTML.
We're dealing with heavy traffic here, so my original choice was the fast
and efficient Cheetah. The main problem is that Cheetah doesn't provide
clear error messages. Even in the best cases, you only get some indication
of the nature of the error ("TypeError: 'str' object is not callable") but
you can't see the code where the error occurs. You can't even know the
approximate region of the template code where the problem originates.
So I tried another templating system, the newer and equally efficient Mako.
Again, same problem. It should be noted that both Cheetah and Mako compile
themselves to an intermediary Python file. This Python file is what's
actually running, so that's where the error originates. This is very
efficient, but also severely hinders debugging (see below for example of
what a very simple error on a very short Mako template generates).
So my question is: is there any way to get clear error messages with a
Python templating system?
I welcome both suggestion on how to get those with Cheetah (or Mako), and
suggestions about alternative templating systems that provide better error
messages.
Thanks,
Tom
-
# foo.mako:
hello ${data}
>>> print mako.template.Template(filename="foo.mako").render(data="world")
hello world
>>> print
mako.template.Template(filename="foo.mako").render(dataerr="world")
Traceback (most recent call last):
File "", line 1, in
File
"/usr/lib/python2.5/site-packages/Mako-0.1.10-py2.5.egg/mako/template.py",
line 114, in render
return runtime._render(self, self.callable_, args, data)
File
"/usr/lib/python2.5/site-packages/Mako-0.1.10-py2.5.egg/mako/runtime.py",
line 287, in _render
_render_context(template, callable_, context, *args,
**_kwargs_for_callable(callable_, data))
File
"/usr/lib/python2.5/site-packages/Mako-0.1.10-py2.5.egg/mako/runtime.py",
line 304, in _render_context
_exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
File
"/usr/lib/python2.5/site-packages/Mako-0.1.10-py2.5.egg/mako/runtime.py",
line 337, in _exec_template
callable_(context, *args, **kwargs)
File "foo_mako", line 19, in render_body
File
"/usr/lib/python2.5/site-packages/Mako-0.1.10-py2.5.egg/mako/runtime.py",
line 91, in __str__
raise NameError("Undefined")
NameError: Undefined
--
http://mail.python.org/mailman/listinfo/python-list
Re: persistent deque (continued)
On Jul 21, 12:08 pm, castironpi <[EMAIL PROTECTED]> wrote: > Some time ago, I was asking about the feasibility of a persistent > deque, a double-ended queue. > > It runs into the typical space allocation problems. Try starting with a dict-based implementation of a double-ended queue ( http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/259179 ) and then replace the dict with a shelf. Presto, you've got a persistent deque. Raymond -- http://mail.python.org/mailman/listinfo/python-list
Re: Converting List of String to Integer
Samir wrote:
On Jul 21, 3:20 pm, Gary Herron <[EMAIL PROTECTED]> wrote:
Samir wrote:
Hi Everyone,
I am relatively new to Python so please forgive me for what seems like
a basic question.
Assume that I have a list, a, composed of nested lists with string
representations of integers, such that
a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
I would like to convert this to a similar list, b, where the values
are represented by integers, such as
b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
I have unsuccessfully tried the following code:
n = []
for k in a:
n.append([int(v) for v in k])
print n
Does anyone know what I am doing wrong?
Thanks in advance.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
You didn't tell us how it failed for you, so I can't guess what's wrong.
However, your code works for me:
>>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
>>> n = []
>>> for k in a:
...n.append([int(v) for v in k])
...
>>> print n
[[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
(Although you seem to have confused variables b and n.)
Gary Herron- Hide quoted text -
- Show quoted text -
Hi Gary,
Thanks for your quick response (and sorry about mixing up b and n).
For some reason, the logic I posted seems to work ok while I'm using
the Python shell, but when used in my code, the program just hangs.
It never outputs the results. Below is the code in its entirety. Is
there a problem with my indendentation?
a = n = []
t = """
1 2
3
4 5 6
7 8 9 0
"""
d = t.split("\n")
for x in range(1,len(d)-1):
a.append(d[x].split(" "))
print a
for k in a:
n.append([int(v) for v in k])
print n
Thanks again.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
I think this will work better, a sub-list comprehension of sorts:
n = [[int(i) for i in k] for k in a]
here is an ipython interactive session using it:
In [1]: a = n = []
In [2]: t = """
...: 1 2
...: 3
...: 4 5 6
...: 7 8 9 0
...: """
In [3]:
In [4]: d = t.split("\n")
In [5]: for x in range(1,len(d)-1):
...: a.append(d[x].split(" "))
...:
...:
In [6]: a
Out[6]: [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
In [7]: n = [[int(i) for i in k] for k in a]
In [8]: n
Out[8]: [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
--
Andrew
--
http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
mk wrote: Seriously, though, would there be any advantage in re-implementing Python in e.g. C++? Considered and rejected by Guido and the CPython developer crew. Anyone who wants C++Python is free to make one, just as people have done JavePython (Jython), C#Python, (IonPython), PythonPython (PyPy), and compiled-CPython (multiple). Not that current implementation is bad, anything but, but if you're not careful, the fact that lists are implemented as C arrays can bite your rear from time to time (it recently bit mine while using lxml). Suppose C++ re-implementation used some other data structure (like linked list, possibly with twists like having an array containing pointers to 1st linked list elements to speed lookups up), which would be a bit slower on average perhaps, but it would behave better re deletion? This is a data structure issue, not a language issue. The tradeoffs for practical implementation include code-length, code-complexity, code-fragility, and ease of cross-platform compilation as well as classical time and space issues. tjr -- http://mail.python.org/mailman/listinfo/python-list
Re: Importing different versions of a module
mercado mercado wrote: I have two versions of a script on my machine. One version is for new development and the other version is a production version. This script imports a module from a different directory, and this module again has two versions (a development version and a production version). What I want is for the development script to import the development module, and the production script to import the production module, without making any changes to the code in the script. if you already have two different versions of the script, what stops you from making changes to them? For example, suppose the development script is in ~/dev/rss.py, and the production script is in ~/prod/rss.py. I want the dev version to import /usr/lib/python2.5/site-packages/lib_dev/parse.py, and the prod version to import usr/lib/python2.5/site-packages/lib_prod/parse.py. cannot you just insert the appropriate directory in sys.path the first thing you do in the scripts? e.g. import os, sys lib = "lib_dev" # change this for prod/rss.py sys.path.insert(0, os.path.join( os.path.dirname(os.__file__), "site-packages", lib )) import parse # picks the right one -- http://mail.python.org/mailman/listinfo/python-list
Re: persistent deque (continued)
On 2008-07-21 21:08, castironpi wrote: Some time ago, I was asking about the feasibility of a persistent deque, a double-ended queue. You might want to have a look at mxBeeBase: http://www.egenix.com/products/python/mxBase/mxBeeBase/ Using the integer index you could probably write an on-disk dequeue. The B*Tree indexes available in mxBeeBase keep the indexes sorted, so you'd only have to keep incrementing the index as you add new values and keep a record of the highest and lowest index currently in use. Details are left as exercise for the interested reader ;-) It runs into the typical space allocation problems. If you're storing a pickle, you have to allocate and fragment the file you've opened, since pickles can be variable-length strings; i.e. if the new data is too long, blank out its entry, and grow the file. If you're storing a data-type, you lose Python's dynamic-type advantages, as well as its long integers, as they can be any length. If you change the object in the deque, such as when using any mutable type, you have to update the container too. Does anyone have any experience storing pickles (I am aware of the similarities to shelf) to a database? Can the file system facilitate the variable-length string problem? How feasible is a length-of-length - length - data solution to the unbounded integer problem? Is there any alternative to completely re-pickling a large (say 1k pickled) object you only change slightly? What other issues are there? Is a hybrid-storage type possible, that stores the contents of its Python-allocated memory block to disk, including reference count, even if it's a lot slower? The object could not contain any references to objects not allocated on disk. A first approach is for the file to look like this: 00 data 01 data 02 01 data 03 data 04 02 data 05 data 06 Append would add: 03 data 07 data 08 AppendLeft would add: -01 data 09 data 0a Pop would remove 03, PopLeft would remove -01. You would need a length-and-head index to make 'rotate' available. Remove would run a worst-case risk of renumbering half of the indices stored, plus a rotate. -- http://mail.python.org/mailman/listinfo/python-list -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Jul 21 2008) >>> Python/Zope Consulting and Support ...http://www.egenix.com/ >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 -- http://mail.python.org/mailman/listinfo/python-list
Re: Change PC to Win or Windows
On Mon, 2008-07-21 at 16:45 -0400, Derek Martin wrote:
> On Mon, Jul 21, 2008 at 12:32:00PM -0700, Lie wrote:
> > > The term "PC" is commonly used in English, in the United States
> > > and other English speaking countries, to mean a computer running
> > > Microsoft Windows.
> >
> > As far as I am aware, they're like that because most people aren't
> > even aware that there are other OSes than Microsoft Windows.
>
> You are missing two points.
>
> The first one: It doesn't matter what the reasons are for the
> terminology to be common. It only matters that it IS common. It is;
> and it is therefore "correct" in the sense that it conveys a meaning
> to the overwhelming majority of English speakers, which is the
> intended one.
>
True, it doesn't actually matters, but it is a proof that it is
technically incorrect to apply PC JUST to Windows-based PC. It is
arguable whether the term should only be exclusively to IBM-PC or
whether the term should be expanded to include its clones. But I'm
against on using it just to refer Windows-based PC exclusively, since
it is neither Microsoft's marketing term nor a literal meaning
conveyed in the term.
> As for the question of whether or not it is appropriate to refer to
> Windows installations as "PC", it's as simple as that. It is, by
> definition (via common usage). That is what this thread is about.
>
Common usage isn't always correct. For example, a physicist would not
use weight when he meant mass. Although in daily use he might not care
much, but in technical environment doing so would embarrass him. In
this analogy, I consider download page for a software source code to
be a technical area.
> The reason why the world hasn't evolved to the two predictable cases
> > ("all kinds of microcomputers" or "IBM-PC and clones"), is what I'll
> > explain below.
>
> Your explanation is irrelevant to the argument of whether or not the
> term PC is an inappropriate term to describe a Windows installation,
> which is what this thread is about. That is the premise put forth by
> the OP, and that is the notion to which I am responding. It simply is
> not wrong or inappropriate in any sense; it is in fact correct,
> regardless of how the meaning or usage resulted, and regardless of any
> ADDITIONAL meanings the term may have.
>
> For what it's worth, your explanation is also WRONG; the term PC
> began to be popularly used in the United States to describe
> Intel-based Microsoft machines when there was a proliferation of other
> kinds of personal computers available to consumers. When it was first
> used this way, the IBM PC was *NOT* the most popular personal computer...
> the Commodore 64 was.
>
True, but PC is IBM's marketing term, thus it originally belongs to
them. Nevertheless, it is NOT Window's marketing term and the literal
meaning of Personal Computer is in no way means Windows-based
computers ONLY.
> It dates from a time when the Commodore VIC-20
> and C64, Atari 400 and 800, Timex Sinclair, and other computers were
> all very popluar home machines.
But they aren't called PC, why? Because IBM hasn't invented the term.
Nowadays, they might be called as PC or not depending on which side
are you in: "PC as IBM-PC" or "PC as personal computer" (note the
lower case)
> The term probably originated primarily because IBM chose to name their
> computer the IBM PC, and because of Americans' predeliction to
> abbreviate everything that's more than 2 syllables. ;-)
>
> > > It wasn't something that Apple started; it's been used this way
> > > in increasingly common usage for at least 20 years, although
> > > exactly what combination of hardware and software was being
> > > refered to as a "PC" has evolved over that timeframe.
> >
> > Apple popularizes the term by explicit marketing,
>
> And here is the last point you are missing: Apple does no such
> thing.
They did, by using the term PC to refer to other computers. IF they
have used the term "Regular PC", noone would have complained, it's
just like an apple farmer advertising his "Super Apples" and calls
other apples "Regular Apples", there would be nothing wrong about it.
But there is this specific apple farmer who advertised his apple as
"Orange" and calls other apples as "Apples", which makes a problem
since "Orange" is just a different variants of apple, and is still an
apple. This kind of advertising Apple (the computer company) used is
misleading, since it implied that their PC is not a PC.
> They are only using a term in a way that has previously been
> popularized by the computer industry as a whole, and its market (i.e.
> consumers, predominantly American consumers historically) for
> *DECADES*.
> If I'm not mistaken, their ad campaign mentioning PCs is
> less than 10 years old (though I can't quickly find any references as
> to the date). The popularization of the term PC to refer to
> Intel-compatible machines running Microsoft OSes PREDATES APPLE'S AD
> CAMPAIGN BY OVER 10 YEARS.
When did I say that Appl
Re: Python Written in C?
Fredrik Lundh wrote: rynt wrote: You're either --- A. A Troll B. A young, immature programmer trying to show off or C. A total idiot. you forgot the "All of the above" choice. Or Aspiring Comic. This is certain one of the more entertaining troll posts we have had ;-). -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting the name of a variable which was used as a function parameter.
Ravi Kotecha wrote: Of course I wouldn't, it is a total hack, mostly useless but fun. I tried to do it after someone in #python efnet said it was impossible! your function only finds *some* name (if it finds a name at all), not *the* name, so you haven't really proven that someone wrong yet. you can get a lot closer by using more radical approaches, but I don't think it's possible to do this in a fully robust way, at least not from the Python level. -- http://mail.python.org/mailman/listinfo/python-list
Re: Trying to solve a python/mechanize "error 500" http error
bruce wrote:
i'm getting the following error:
mechanize._response.httperror_seek_wrapper: HTTP Error 500:
i'm running python 5.1
and mechanize 0.1.7b
I have no idea as to what I have to change/modify/include to handle this
issue. The link that I'm testing is at the bottom of the page. When I insert
the link into the browser, I actually get an err page.. so, I suspect that
there is a handler that I should be able to modify/use to handle this
situation...
Thoughts/Comments will be greatly appreciated...
Thanks
the output is:
www = www.1800ink.com
url2= http://www.quantcast.com/www.1800ink.com/traffic
Traceback (most recent call last):
File "./reseller_scrape_child.py", line 288, in
q1 = shopfuncs.quant(rhref)
File "/adkiller/shopfuncs.py", line 56, in quant
br.open(url2)
File "build/bdist.linux-x86_64/egg/mechanize/_mechanize.py", line 203, in
open
File "build/bdist.linux-x86_64/egg/mechanize/_mechanize.py", line 254, in
_mech_open
mechanize._response.httperror_seek_wrapper: HTTP Error 500:
[EMAIL PROTECTED] adkiller]# ./reseller_scrape_child.py
my code segment looks like:
from mechanize import Browser
import mechanize
br = Browser()
user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
values1 = {'name' : 'Michael Foord',
'location' : 'Northampton',
'language' : 'Python' }
headers = { 'User-Agent' : user_agent }
#br.set_cookiejar(cj)
br.set_handle_redirect(True)
br.set_handle_referer(True)
br.set_handle_robots(False)
br.addheaders = [('User-Agent', 'Firefox')]
url2 ="http://www.quantcast.com//traffic";
#gets the page (url) from the quantcast app
url2=url2.replace("",url)
print "url2=",url2
br.open(url2)
===
this works ok for most of the sites.. but something weird is happening with
the actual page:
http://www.quantcast.com/www.1800ink.com/traffic
thanks...
Looking up 500 error (here
http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html)
gives me:
10.5.1 500 Internal Server Error
The server encountered an unexpected condition which prevented it from
fulfilling the request.
On some servers (Amazon), when you get 500 errors you are instructed to try
the request again. I don't know about this server.
-Larry
--
http://mail.python.org/mailman/listinfo/python-list
Re: Importing different versions of a module
mercado mercado wrote: Thanks norseman for the reply. You're right that I didn't like it though. :-) Also note that my original question has to do with importing modules from different locations. If all I had to do was use different paths within the script (e.g. for sending to os.path.join or whatever), then I could just put those in a config file. That's not a problem... -- http://mail.python.org/mailman/listinfo/python-list === I started to import a module using its path and now see what you mean. Python is missing the concept: Programmer dictates what machine does. (I come from assembly. If the hardware can do it, so can I.) sys.path can be modified to switch between file sets (prod/test). if a global is set one way, use the normal paths, if set another, modify the needed to force the test_section into use. Unfortunately this is not much of an answer. It means hardcoding two paths into globals and using a third to control which is used. Since Python has a habit of coming and going on its own this may not work in a major effort. It may unload something and later reload with the sys.path set wrong. Docs say it will reload file that did load originally even if the file was modified between loads. Docs do not say it keeps original location. I'll need some time to set things up to test what it does. Nothing I've done in Python had bumped into your problem until I ran the test. Never dawned on me it would be this stupid. I had intended to use Python to talk to ESRI products and my stuff. I made a few minor routines just to get used to Python and was starting to tackle the real problem. My assembly, C, fortran & bash scripts all work as expected. They do, Python doesn't. ORIGINALLY, IN THIS REPLY, I HAD STARTED TO SAY: I've used this before. Maybe it will work in Python, maybe not. Global sets which section to use by being a prefix to each test module name. Something like "my_" for test and empty otherwise. global WHICH WHICH='my_' import WHICH+'subrtn' WHICH='' import WHICH+'subrtn2' gets my_subrtn from the test suite and gets subrtn2 from the production section. Each module would thus need to store/reset the Global's value upon init to be used in its own imports since it's status at any given time is in question. Python docs say Python keeps the original name of the originally successfully loaded file. The built-in 'reload' can get it back, even if it has been changed (edited) during the session. The files my_ whatever have the my_ removed from the disk name when they go production. # BUT import WILL NOT TAKE VARS # OK check#1 Python 2.5.2 (r252:60911, Mar 4 2008, 10:40:55) [GCC 3.3.6] on linux2 Type "help", "copyright", "credits" or "license" for more information. WHICH="my_" import WHICH+"popen2" File "", line 1 import WHICH+"popen2" ^ SyntaxError: invalid syntax OK check#2 x=WHICH+"open2" x 'my_open2' import x Traceback (most recent call last): File "", line 1, in ImportError: No module named x OK check#3 help(x) no Python documentation found for 'my_open2'#true, proves x OK BOY-O-BOY, DOES THAT SCREW THE POOCH Mercado, like you, I'm not very happy right now. This means that prefixing cannot be used to control imports. For decades I have used prefixing in both scripts and compiled lib routines for controlling what gets loaded or not. Right now I'm not a happy Python camper, not at all. Steve [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: imported module no longer available
Jeff Dyke wrote: actually no, the only things in that fucntion were. print globals().keys() - i see it here print mymodulename - it fails here. the `import mymodulename` statement is at the very top of the file. plus the processing that was attempted after. so how did that processing use the "mymodulename" name? >> in fact in the calling method i was able to execute print mymodulename and it printed the expected python output. the calling method has nothing to do with what's considered to be a local variable in the method being called, so that only means that the name is indeed available in the global scope. So i went back to check that the name 'mymodulename' was not getting overwritten by something else and the error went away. I've been working on something else entirely for the past few hours and have changed none of the code...and now it works. which is even more troublesome then the error itself. more likely, it indicates that you removed the line that caused Python to treat that name as a local variable. Follow on question. If this name, mymodulename, was imported in some other module.fucntion local to a function like def anotherfunc(): import mymodulename would that remove it from the globals() and save it to a locals() ? I would assume the answer to be no. even after reading the page I pointed you to? import binds a name, so an import statement inside a function will cause Python to treat that name as a local variable (unless you add a global declaration to that function). maybe a few examples will make this clearer; the following snippets are complete programs: snippet 1: import module # adds module to the global namespace def func(): module.func() # uses module from the global namespace func() # no error here snippet 2: def func(): import module # adds module to the *local* namespace module.func() func() # no error here module.func() # doesn't work; no module in global namespace snippet 3: def func(): global module # marks module as a global name import module # adds module to the *global* namespace module.func() func() # no error here module.func() # no error here; global module set by function snippet 4: import module # adds module to global namespace def func(): import module # adds module to local namespace too print module # prints local variable module = None # sets local variable to None func() # no error here module.func() # no error here either; uses global namespace snippet 5: import module def func(): print module # fails with an UnboundLocalError. # lots of lines import module # adds to local namespace; marks name as local # some more code func() # will fail at print statement my guess is that the last snippet corresponds to your case. -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting the name of a variable which was used as a function parameter.
Of course I wouldn't, it is a total hack, mostly useless but fun. I tried to do it after someone in #python efnet said it was impossible! On Jul 21, 9:56 pm, Marc 'BlackJack' Rintsch <[EMAIL PROTECTED]> wrote: > On Mon, 21 Jul 2008 09:01:10 -0700, Ravi Kotecha wrote: > > I thought this was pretty cool and since I spent 30 mins or so > > goggling before giving up and figuring out myself I thought I'd share > > it with you. > > def a(a): > > ... for k,v in sys._getframe(1).f_locals.items(): > > ... if id(v) == id(a): > > ... print k > > ... > > hello = 123 > > a(hello) > > hello > > > ## pretty cool. > > Or ugly hack. Beauty lies in the eye of the beer holder… > > > It's totally useless but I wanted to do it for logging purposes. > > Don't use such things in production code, please. > > Ciao, > Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
RE: Python Written in C?
On 20 jul, 19:50, [EMAIL PROTECTED] wrote: > I'm just learning about Python now and it sounds interesting. But I > just read (on the Wiki page) that mainstream Python was written in C. > That's what I was searching for: Python was written in what other > language? > > See, my concern was something like: OK, if Python is so hot, then, > hopefully someone is writing it in assembly language for each MPU chip > out there. Otherwise, if, say, they've written it in C#, then it looks > like the REAL, generally useful language to learn is C# and Python is > akin to Visual Basic or something: a specialty languagewhereas > REAL WORLD programmers who want to be generally useful go and learn > C#. > > So I was suspecting the Python compiler or interpreter is written in a ".. if Python is so hot.." Python represents progress not the ultimate goal. Thank goodness we are continuing to learn from past mistakes. All compilers and interpreters started out being written in another language. You do not help us by stating the obvious. This is even true of the interpreter in your own brain that processes English. IMHO The latter still has some bugs in it. ;-) -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Mon, 21 Jul 2008 11:26:27 -0700, castironpi wrote: > On Jul 20, 11:59 pm, Michael Torrie <[EMAIL PROTECTED]> wrote: >> [EMAIL PROTECTED] wrote: >> > I'm not dissing Python, here. Just noting that, if it is written in C, >> > that throws a curve at me in trying to balance the value of learning >> > Python vs. some other major language. >> >> Definitely one of the most non-sequitor statements I have ever heard. >> Actually your entire post doesn't make much sense. Maybe you are a >> brother bot to castropini? Perhaps a less-trained one, although none of >> castropini's posts seem to make sense either. The AI needs a bit of work. > > Are you saying Python is not good for writing A.I., or the A.I. isn't > good at writing Python? Are you saying python is not as smart as you. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting the name of a variable which was used as a function parameter.
On Mon, 21 Jul 2008 09:01:10 -0700, Ravi Kotecha wrote: > I thought this was pretty cool and since I spent 30 mins or so > goggling before giving up and figuring out myself I thought I'd share > it with you. > def a(a): > ... for k,v in sys._getframe(1).f_locals.items(): > ... if id(v) == id(a): > ... print k > ... > hello = 123 > a(hello) > hello > > ## pretty cool. Or ugly hack. Beauty lies in the eye of the beer holder… > It's totally useless but I wanted to do it for logging purposes. Don't use such things in production code, please. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: Seriously, though, about LLVM
mk wrote: This project has gained some publicity. There's IronPython, right, so has anybody thought about implementing Python using LLVM as backend, as it seems not out of question at all? you mean like: http://llvm.org/ProjectsWithLLVM/#pypy ? No, I don't mean "Python written in Python", with whatever backend. so anyone attempting to write a Python implementation for the LLVM aren't allowed to use Python for the front-end? why not? -- http://mail.python.org/mailman/listinfo/python-list
Re: Converting List of String to Integer
On Jul 21, 4:44 pm, Gary Herron <[EMAIL PROTECTED]> wrote:
> Samir wrote:
> > On Jul 21, 3:20 pm, Gary Herron <[EMAIL PROTECTED]> wrote:
>
> >> Samir wrote:
>
> >>> Hi Everyone,
>
> >>> I am relatively new to Python so please forgive me for what seems like
> >>> a basic question.
>
> >>> Assume that I have a list, a, composed of nested lists with string
> >>> representations of integers, such that
>
> >>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
>
> >>> I would like to convert this to a similar list, b, where the values
> >>> are represented by integers, such as
>
> >>> b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
>
> >>> I have unsuccessfully tried the following code:
>
> >>> n = []
> >>> for k in a:
> >>> n.append([int(v) for v in k])
> >>> print n
>
> >>> Does anyone know what I am doing wrong?
>
> >>> Thanks in advance.
>
> >>> Samir
> >>> --
> >>>http://mail.python.org/mailman/listinfo/python-list
>
> >> You didn't tell us how it failed for you, so I can't guess what's wrong.
>
> >> However, your code works for me:
>
> >> >>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
> >> >>> n = []
> >> >>> for k in a:
> >> ... n.append([int(v) for v in k])
> >> ...
> >> >>> print n
> >> [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
>
> >> (Although you seem to have confused variables b and n.)
>
> >> Gary Herron- Hide quoted text -
>
> >> - Show quoted text -
>
> > Hi Gary,
>
> > Thanks for your quick response (and sorry about mixing up b and n).
> > For some reason, the logic I posted seems to work ok while I'm using
> > the Python shell, but when used in my code, the program just hangs.
> > It never outputs the results. Below is the code in its entirety. Is
> > there a problem with my indendentation?
>
> Aha. There's the problem, right there in the first line.
>
> > a = n = []
>
> This sets a and n to the *same* empty list. This line creates one
> empty list and binds both n and a to that list. Note carefully, there
> is only one empty list here, but it can be accessed under two names
>
> Later in your code,
>
> for k in a:
>
> runs through that list, and
>
> n.append(...)
>
> append to the end of the same list. Thus the loop never get to the end of
> the (continually growing) list.
>
> Solve it by creating two different empty lists:
>
> a = []
> n = []
>
> Gary Herron
>
>
>
> > t = """
> > 1 2
> > 3
> > 4 5 6
> > 7 8 9 0
> > """
>
> > d = t.split("\n")
>
> > for x in range(1,len(d)-1):
> > a.append(d[x].split(" "))
> > print a
>
> > for k in a:
> > n.append([int(v) for v in k])
>
> > print n
>
> > Thanks again.
>
> > Samir
> > --
> >http://mail.python.org/mailman/listinfo/python-list- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
Gary,
That did the trick! I didn't realize that the way I initialized my
lists would lead to the behavior that I observed. After doing
something similar to what John had suggested I did indeed discover
that I created an endless loop. I'm glad I learned something today.
Thanks for your help.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
Re: Change PC to Win or Windows
On Mon, Jul 21, 2008 at 12:32:00PM -0700, Lie wrote:
> > The term "PC" is commonly used in English, in the United States
> > and other English speaking countries, to mean a computer running
> > Microsoft Windows.
>
> As far as I am aware, they're like that because most people aren't
> even aware that there are other OSes than Microsoft Windows.
You are missing two points.
The first one: It doesn't matter what the reasons are for the
terminology to be common. It only matters that it IS common. It is;
and it is therefore "correct" in the sense that it conveys a meaning
to the overwhelming majority of English speakers, which is the
intended one.
As for the question of whether or not it is appropriate to refer to
Windows installations as "PC", it's as simple as that. It is, by
definition (via common usage). That is what this thread is about.
> The reason why the world hasn't evolved to the two predictable cases
> ("all kinds of microcomputers" or "IBM-PC and clones"), is what I'll
> explain below.
Your explanation is irrelevant to the argument of whether or not the
term PC is an inappropriate term to describe a Windows installation,
which is what this thread is about. That is the premise put forth by
the OP, and that is the notion to which I am responding. It simply is
not wrong or inappropriate in any sense; it is in fact correct,
regardless of how the meaning or usage resulted, and regardless of any
ADDITIONAL meanings the term may have.
For what it's worth, your explanation is also WRONG; the term PC
began to be popularly used in the United States to describe
Intel-based Microsoft machines when there was a proliferation of other
kinds of personal computers available to consumers. When it was first
used this way, the IBM PC was *NOT* the most popular personal computer...
the Commodore 64 was. It dates from a time when the Commodore VIC-20
and C64, Atari 400 and 800, Timex Sinclair, and other computers were
all very popluar home machines.
The term probably originated primarily because IBM chose to name their
computer the IBM PC, and because of Americans' predeliction to
abbreviate everything that's more than 2 syllables. ;-)
> > It wasn't something that Apple started; it's been used this way
> > in increasingly common usage for at least 20 years, although
> > exactly what combination of hardware and software was being
> > refered to as a "PC" has evolved over that timeframe.
>
> Apple popularizes the term by explicit marketing,
And here is the last point you are missing: Apple does no such
thing. They are only using a term in a way that has previously been
popularized by the computer industry as a whole, and its market (i.e.
consumers, predominantly American consumers historically) for
*DECADES*. If I'm not mistaken, their ad campaign mentioning PCs is
less than 10 years old (though I can't quickly find any references as
to the date). The popularization of the term PC to refer to
Intel-compatible machines running Microsoft OSes PREDATES APPLE'S AD
CAMPAIGN BY OVER 10 YEARS.
Therefore none of your points are valid or relevant, as to the
question of whether the usage of the term "PC" to describe windows
builds of Python is appropriate.
Can we return to the subject of Python now?
--
Derek D. Martin
http://www.pizzashack.org/
GPG Key ID: 0x81CFE75D
pgpaJhm9UM6EY.pgp
Description: PGP signature
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Re: Converting List of String to Integer
Samir wrote:
On Jul 21, 3:20 pm, Gary Herron <[EMAIL PROTECTED]> wrote:
Samir wrote:
Hi Everyone,
I am relatively new to Python so please forgive me for what seems like
a basic question.
Assume that I have a list, a, composed of nested lists with string
representations of integers, such that
a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
I would like to convert this to a similar list, b, where the values
are represented by integers, such as
b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
I have unsuccessfully tried the following code:
n = []
for k in a:
n.append([int(v) for v in k])
print n
Does anyone know what I am doing wrong?
Thanks in advance.
Samir
--
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You didn't tell us how it failed for you, so I can't guess what's wrong.
However, your code works for me:
>>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
>>> n = []
>>> for k in a:
...n.append([int(v) for v in k])
...
>>> print n
[[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
(Although you seem to have confused variables b and n.)
Gary Herron- Hide quoted text -
- Show quoted text -
Hi Gary,
Thanks for your quick response (and sorry about mixing up b and n).
For some reason, the logic I posted seems to work ok while I'm using
the Python shell, but when used in my code, the program just hangs.
It never outputs the results. Below is the code in its entirety. Is
there a problem with my indendentation?
Aha. There's the problem, right there in the first line.
a = n = []
This sets a and n to the *same* empty list.This line creates one
empty list and binds both n and a to that list. Note carefully, there
is only one empty list here, but it can be accessed under two names
Later in your code,
for k in a:
runs through that list, and
n.append(...)
append to the end of the same list. Thus the loop never get to the end of the
(continually growing) list.
Solve it by creating two different empty lists:
a = []
n = []
Gary Herron
t = """
1 2
3
4 5 6
7 8 9 0
"""
d = t.split("\n")
for x in range(1,len(d)-1):
a.append(d[x].split(" "))
print a
for k in a:
n.append([int(v) for v in k])
print n
Thanks again.
Samir
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Re: sending input to an embedded application
Matthew Fitzgibbons wrote:
mefyl wrote:
Uwe Schmitt wrote:
On 12 Jul., 09:08, George Oliver <[EMAIL PROTECTED]> wrote:
What I would like to do is take a program and embed it or put it
within a Python-run GUI, using the GUI just to capture and send input
to the application, and display the ouput.
Which interface does your interpreter provide ? Just commandline or
can you access by other methods ?
http://sourceforge.net/projects/pexpect/ might help you
Although Pexpect looks more advanced and complete, you might want to
take a
look at popen* modules. It enables you to easily run a subprocess,
feed him
data on stdin, retrieve output from stdout/stderr, and wait for its
completion.
http://docs.python.org/lib/module-popen2.html
I believe the subprocess module is the recommended module to use now.
-Matt
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=
HUMM!
#
print "popen3 run"
## from existing python docs:
from popen2 import *
r,w,e= popen3('dmesg | grep hda')
print r.read()
print "subprocess run"
## from existing python docs:
# "... Replacing older functions with the subprocess module..."
from subprocess import *
p1 = Popen(["dmesg"], stdout=PIPE)
p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]
#documentation quits
print p2.communicate()
#
""" Why do children insists on making things more complicated
than necessary? If the stated bragging rights of Python
is that one writes less code to accomplish more, then I
have to say "bullshit", just count the printable characters.
to write less would be to change something like this:
try:
f = open(arg, 'r')
except IOError:
print 'cannot open', arg
else:
print arg, 'has', len(f.readlines()), 'lines'
f.close()
### I have to guess what type error to code for and I'll need another
module to decode what actually went wrong.
to this:
if (fd = os.open(filename, 'O_RDRW|O_BINARY, 0666) == -1)
...handle it
if fd.err.type == THIS #catagory
if fd.err == this#specific
do this
etc.
## just to see what went wrong? print fd.err.type, fd.err
else:#just to match above
continue processing
### error reporting actually usefull
who says fd cannot be simple interger or pointer to error block
depending on whether it's valid or not? The bonus is, if there is
no trap it will stop anyway first time fd is used as a file number.
The crash usually actually points to the correct place. :)
All that aside: subprocess seems to have a problem:
"""
# When I run the above I get:
==
PY:> py test.py
popen3 run
ide0: BM-DMA at 0x1400-0x1407, BIOS settings: hda:DMA, hdb:pio
hda: ST9160821A, ATA DISK drive
hda: attached ide-disk driver.
hda: host protected area => 1
hda: cannot use LBA48 - capacity reset from 312581808 to 268435456
hda: 268435456 sectors (137439 MB) w/8192KiB Cache, CHS=19457/255/63,
UDMA(100)
hda: hda1 hda2 hda3 < hda5 hda6 hda7 hda8 >
subprocess run
('', None)
PY:>
=
Note subprocess yields unexpected answer. Probably needs better
documentation and less typing. :)
The "PY:> " is result of script to change to dir python and set the PATH
py is copy of python renamed to afford less typing. (Unix vs Microsoft)
Note: without lots of extra effort, the piping only works for commands
like grep that are built to accept redirected I/O. I have yet to get it
to work with the GUI type. Those need special things implanted at
compile time because they don't use or even want the command line
interface. Typically they are "Point'n'Click" or take a hike. GUIs are
visually more appealing but don't play well in the production world.
Steve
[EMAIL PROTECTED]
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Re: Missing sqlite3.h Error when Building Debug Python -- Windows Vista
Thanks for letting me know about this. I installed Subversion and tried to make the build work like that, but it fails. 1) I am building 64-bit on Vista, so I used build-amd64.bat instead of build.bat. 2) build-amd64.bat was setup to use MSVS 9.0, while I am using MSVS 8.0. Also, some of the BATCH programs incorrectly added a backslash after the %VS90COMNTOOLS% environment variable. I corrected those to use %VS80COMNTOOLS%, without the backslash. 3) It then complained about incompatible solution/project files, so I modified build-amd64.bat to use the solution/project files in pc\vs8.0 instead of pcbuild. 4) It now has errors/warnings like: C:\Program Files (x86)\Microsoft Visual Studio 8\VC\PlatformSDK\include \prsht.h(531) : error C2016: C requires that a struct or union has at least one member ... c1 : fatal error C1083: Cannot open source file: '..\..\.. \db-4.4.20\common\zerofill.c': No such file or directory xa_map.c ... 4>..\..\Python\getargs.c(319) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data So I don't see how the amd64-bit builds are working out of the box on MS Windows Vista, and I may have made some error when changing the build files. I'd appreciate any other thoughts ... Bev in TX On Jul 20, 10:36 am, Tim Golden <[EMAIL PROTECTED]> wrote: > I'll leave others to comment on whether or not > it's expected to build with VS2005, but the easiest > way to get a debug build is to pretend to be a buildbot. > > 1) Check out the python source into, say, c:\dev\python > > svn cohttp://svn.python.org/projects/python/trunkc:\dev\python > > 2) Switch to that directory > > cd \dev\python > > 3) Pretend to be a buildbot > > tools\buildbot\build > > This will checkout all the necessary sources into, in my > example, c:\dev. It will then run all the build steps > necessary to get a debug build which will then be in > > c:\dev\python\pcbuild\python_d.exe > > TJG -- http://mail.python.org/mailman/listinfo/python-list
Re: Converting List of String to Integer
On Jul 22, 6:11 am, Samir <[EMAIL PROTECTED]> wrote:
[snip]
> For some reason, the logic I posted seems to work ok while I'm using
> the Python shell, but when used in my code, the program just hangs.
> It never outputs the results. Below is the code in its entirety. Is
> there a problem with my indendentation?
>
> a = n = []
> t = """
> 1 2
> 3
> 4 5 6
> 7 8 9 0
> """
>
> d = t.split("\n")
>
> for x in range(1,len(d)-1):
> a.append(d[x].split(" "))
> print a
>
> for k in a:
> n.append([int(v) for v in k])
To see what is happening, insert some print statements, plus something
to slow it down e.g.
for k in a:
print id(a), a
print id(n), n
n.append([int(v) for v in k])
raw_input('Hit Enter to continue ->')
>
> print n
>
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Trying to solve a python/mechanize "error 500" http error
i'm getting the following error:
mechanize._response.httperror_seek_wrapper: HTTP Error 500:
i'm running python 5.1
and mechanize 0.1.7b
I have no idea as to what I have to change/modify/include to handle this
issue. The link that I'm testing is at the bottom of the page. When I insert
the link into the browser, I actually get an err page.. so, I suspect that
there is a handler that I should be able to modify/use to handle this
situation...
Thoughts/Comments will be greatly appreciated...
Thanks
the output is:
www = www.1800ink.com
url2= http://www.quantcast.com/www.1800ink.com/traffic
Traceback (most recent call last):
File "./reseller_scrape_child.py", line 288, in
q1 = shopfuncs.quant(rhref)
File "/adkiller/shopfuncs.py", line 56, in quant
br.open(url2)
File "build/bdist.linux-x86_64/egg/mechanize/_mechanize.py", line 203, in
open
File "build/bdist.linux-x86_64/egg/mechanize/_mechanize.py", line 254, in
_mech_open
mechanize._response.httperror_seek_wrapper: HTTP Error 500:
[EMAIL PROTECTED] adkiller]# ./reseller_scrape_child.py
my code segment looks like:
from mechanize import Browser
import mechanize
br = Browser()
user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
values1 = {'name' : 'Michael Foord',
'location' : 'Northampton',
'language' : 'Python' }
headers = { 'User-Agent' : user_agent }
#br.set_cookiejar(cj)
br.set_handle_redirect(True)
br.set_handle_referer(True)
br.set_handle_robots(False)
br.addheaders = [('User-Agent', 'Firefox')]
url2 ="http://www.quantcast.com//traffic";
#gets the page (url) from the quantcast app
url2=url2.replace("",url)
print "url2=",url2
br.open(url2)
===
this works ok for most of the sites.. but something weird is happening with
the actual page:
http://www.quantcast.com/www.1800ink.com/traffic
thanks...
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Trying to solve a python/mechanize "error 500" http error
i'm getting the following error:
mechanize._response.httperror_seek_wrapper: HTTP Error 500:
i'm running python 5.1
and mechanize 0.1.7b
I have no idea as to what I have to change/modify/include to handle this
issue. The link that I'm testing is at the bottom of the page. When I insert
the link into the browser, I actually get an err page.. so, I suspect that
there is a handler that I should be able to modify/use to handle this
situation...
Thoughts/Comments will be greatly appreciated...
Thanks
the output is:
www = www.1800ink.com
url2= http://www.quantcast.com/www.1800ink.com/traffic
Traceback (most recent call last):
File "./reseller_scrape_child.py", line 288, in
q1 = shopfuncs.quant(rhref)
File "/adkiller/shopfuncs.py", line 56, in quant
br.open(url2)
File "build/bdist.linux-x86_64/egg/mechanize/_mechanize.py", line 203, in
open
File "build/bdist.linux-x86_64/egg/mechanize/_mechanize.py", line 254, in
_mech_open
mechanize._response.httperror_seek_wrapper: HTTP Error 500:
[EMAIL PROTECTED] adkiller]# ./reseller_scrape_child.py
my code segment looks like:
from mechanize import Browser
import mechanize
br = Browser()
user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
values1 = {'name' : 'Michael Foord',
'location' : 'Northampton',
'language' : 'Python' }
headers = { 'User-Agent' : user_agent }
#br.set_cookiejar(cj)
br.set_handle_redirect(True)
br.set_handle_referer(True)
br.set_handle_robots(False)
br.addheaders = [('User-Agent', 'Firefox')]
url2 ="http://www.quantcast.com//traffic";
#gets the page (url) from the quantcast app
url2=url2.replace("",url)
print "url2=",url2
br.open(url2)
===
this works ok for most of the sites.. but something weird is happening with
the actual page:
http://www.quantcast.com/www.1800ink.com/traffic
thanks...
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Re: Converting List of String to Integer
On Jul 21, 3:20 pm, Gary Herron <[EMAIL PROTECTED]> wrote:
> Samir wrote:
> > Hi Everyone,
>
> > I am relatively new to Python so please forgive me for what seems like
> > a basic question.
>
> > Assume that I have a list, a, composed of nested lists with string
> > representations of integers, such that
>
> > a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
>
> > I would like to convert this to a similar list, b, where the values
> > are represented by integers, such as
>
> > b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
>
> > I have unsuccessfully tried the following code:
>
> > n = []
> > for k in a:
> > n.append([int(v) for v in k])
> > print n
>
> > Does anyone know what I am doing wrong?
>
> > Thanks in advance.
>
> > Samir
> > --
> >http://mail.python.org/mailman/listinfo/python-list
>
> You didn't tell us how it failed for you, so I can't guess what's wrong.
>
> However, your code works for me:
>
> >>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
> >>> n = []
> >>> for k in a:
> ... n.append([int(v) for v in k])
> ...
> >>> print n
> [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
>
> (Although you seem to have confused variables b and n.)
>
> Gary Herron- Hide quoted text -
>
> - Show quoted text -
Hi Gary,
Thanks for your quick response (and sorry about mixing up b and n).
For some reason, the logic I posted seems to work ok while I'm using
the Python shell, but when used in my code, the program just hangs.
It never outputs the results. Below is the code in its entirety. Is
there a problem with my indendentation?
a = n = []
t = """
1 2
3
4 5 6
7 8 9 0
"""
d = t.split("\n")
for x in range(1,len(d)-1):
a.append(d[x].split(" "))
print a
for k in a:
n.append([int(v) for v in k])
print n
Thanks again.
Samir
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Re: persistent deque (continued)
castironpi wrote: Some time ago, I was asking about the feasibility of a persistent deque, a double-ended queue. It runs into the typical space allocation problems. If you're storing a pickle, you have to allocate and fragment the file you've opened, since pickles can be variable-length strings; i.e. if the new data is too long, blank out its entry, and grow the file. If you're storing a data-type, you lose Python's dynamic-type advantages, as well as its long integers, as they can be any length. If you change the object in the deque, such as when using any mutable type, you have to update the container too. Does anyone have any experience storing pickles (I am aware of the similarities to shelf) to a database? Can the file system facilitate the variable-length string problem? How feasible is a length-of-length - length - data solution to the unbounded integer problem? Is there any alternative to completely re-pickling a large (say 1k pickled) object you only change slightly? What other issues are there? Is a hybrid-storage type possible, that stores the contents of its Python-allocated memory block to disk, including reference count, even if it's a lot slower? The object could not contain any references to objects not allocated on disk. A first approach is for the file to look like this: 00 data 01 data 02 01 data 03 data 04 02 data 05 data 06 Append would add: 03 data 07 data 08 AppendLeft would add: -01 data 09 data 0a Pop would remove 03, PopLeft would remove -01. You would need a length-and-head index to make 'rotate' available. Remove would run a worst-case risk of renumbering half of the indices stored, plus a rotate. It is so much easier to implement this using a database table that IMHO most people would go that route. -Larry -- http://mail.python.org/mailman/listinfo/python-list
Re: scanf in python
I'm pretty certain python won't grow an additional operator for this. Yet you are free to create a scanf-implementation as 3rd-party-module. IMHO the usability of the approach is very limited though. First of all, the need to capture more than one input token is *very* seldom - nearly all commandline-tools I know that do require interactive user-input (like the linux kernel config tool) do so by providing either line-by-line value entry (including defaults, something you can't do with your approach), or even dialog-centric value entry with curses. So - I doubt you will gather much momentum on this. Good luck though. Diez Actually it is quite common, it is used for processing of files not for reading parameters. You can use it whenever you need to read a simple csv file or fixed format file which contains many lines with several fields per line. The advantage of the approach is that it combines the parsing and conversion of the fields into one operation. Another advantage of using simple formatting strings is that it allows for easy translation of these lines, just like you have with the % operator for output. I don't see why python can have an operator for output but it can't have one for input, it's just not symmetrical. I don´t see why you can't use this method for line-by-line value entry, just add \n between your %s or %d. The method is quite versatile and much simpler than regular expressions plus conversion afterwards. André -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
Mensanator schrieb: You want cool? THIS is cool: j = ((invert(xyz[1]-xyz[0],xyz[1]**(k-1))*(xyz[1]**(k-1)-prev_gen[2])) % xyz[1]**(k-1))/xyz[1]**(k-2) You call it cool, I call it NameError: name 'invert' is not defined. Regards, Johannes -- "Wer etwas kritisiert muss es noch lange nicht selber besser können. Es reicht zu wissen, daß andere es besser können und andere es auch besser machen um einen Vergleich zu bringen." - Wolfgang Gerber in de.sci.electronics <[EMAIL PROTECTED]> -- http://mail.python.org/mailman/listinfo/python-list
Re: Change PC to Win or Windows
> It very much IS the point. Language evolves based on common usage
> patterns of the people who use it.
That is inarguably correct.
> The term "PC" is commonly used in English, in the United States
> and other English speaking countries, to mean a computer running
> Microsoft Windows.
As far as I am aware, they're like that because most people aren't
even aware that there are other OSes than Microsoft Windows. If the
world is still back in the 80s or 90s when people that use computers
means they're knowledgeable enough about computer, PCs would be either
applied to "all kinds of small computer/microcomputer" or only to "IBM-
branded microcomputers", the latter because PC is originally IBM's
marketing term, the former is a natural expansion of the meaning since
"Personal Computer" is a neutral term, unlike marketing terms like:
"TravelMate", "Lifebook", "MacBook", "GeForce", etc. "Personal
Computer" is more like the term "Mobile Phone" which is brand-neutral
and is usable by any brand, regardless of how the term originated.
The reason why the world hasn't evolved to the two predictable cases
("all kinds of microcomputers" or "IBM-PC and clones"), is what I'll
explain below.
> That's a simple fact that you can not escape, no matter how
> much you may not like it (it just so happens that I also don't l
> ike it, but I realized long ago the futility of arguing against
> its usage). It's still a fact, and I described roughly how
> that fact came to be.
> It wasn't something that Apple started; it's been used this way
> in increasingly common usage for at least 20 years, although
> exactly what combination of hardware and software was being
> refered to as a "PC" has evolved over that timeframe.
Apple popularizes the term by explicit marketing, but the real blame
is to Microsoft's dominance, though it is without their explicit
consent, blessing, or resistance. Not entirely Microsoft's fault for
being dominant, but their dominance in the lower level users makes
those lower level user unaware of other OSes and applied the term PC
to Windows-based computers. When other OSes are gaining popularity
again (i.e. when Microsoft starts to lose its total and complete
dominance, i.e. around right now) the term's meaning become a huge
matter because people associated the term with Microsoft Windows (i.e.
software), not with IBM-PC and its clones anymore (i.e. hardware).
On Jul 21, 11:50 pm, Derek Martin <[EMAIL PROTECTED]> wrote:
> On Sat, Jul 19, 2008 at 02:56:07AM -0700, Lie wrote:
> > government, etc. IBM PC is one of the first computers that ordinary
> > people could possess, when IBM-clones appeared on the market, they're
> > referred as PCs too because they are Personal Computer, a computer
> > that is designed for personal use.
>
> Just to be clear, this statement is WRONG. PC-clones were so called
> because they were clones of the IBM-PC. The term is very specific to
> IBM-compatible hardware.
>
> http://en.wikipedia.org/wiki/Pc_clone
>
> IBM PC compatible computers are those generally similar to the
> original IBM PC, XT, and AT. Such computers used to be referred to
> as PC clones, or IBM clones since they almost exactly duplicated
> all the significant features of the PC, XT, or AT internal design,
> facilitated by various manufacturers' ability to legally reverse
> engineer the BIOS through cleanroom design.
>
> Wikipedia's article on the personal computer accurately reflects
> the multiple meanings of the term, and points out the common usage
> to mean a Windows box:
>
> http://en.wikipedia.org/wiki/Personal_computer
>
> Today a PC may be a desktop computer, a laptop computer or a
> tablet computer. The most common operating systems are Microsoft
> Windows, Mac OS X and Linux, while the most common microprocessors
> are x86 compatible CPUs. However, the term "PC" is often used
> only to refer to computers running Microsoft Windows.
>
> So please stop your whining and get used to the idea that THE REST OF
> THE WORLD uses PC to mean a Windows box.
The rest of the world? Not in this part of the world, not in my whole
country at the least...
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Re: Converting List of String to Integer
Samir wrote: Hi Everyone, I am relatively new to Python so please forgive me for what seems like a basic question. Assume that I have a list, a, composed of nested lists with string representations of integers, such that a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']] I would like to convert this to a similar list, b, where the values are represented by integers, such as b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]] I have unsuccessfully tried the following code: n = [] for k in a: n.append([int(v) for v in k]) print n Does anyone know what I am doing wrong? Thanks in advance. Samir -- http://mail.python.org/mailman/listinfo/python-list You didn't tell us how it failed for you, so I can't guess what's wrong. However, your code works for me: >>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']] >>> n = [] >>> for k in a: ...n.append([int(v) for v in k]) ... >>> print n [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]] (Although you seem to have confused variables b and n.) Gary Herron -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
Let's say you want to build a house... You can use pre-built bricks and stack them together to build your walls, or you can cook your own bricks out of clay because hey! clay is the real thing not those ready-made bricks that anyone can use! In the end, you'll have a truly original house but you would have spent 5 years instead of 6 months. The question is: Is it worth it? Bceause you can use pre-built bricks instead and, after applying stucco, nobody will notice you used bricks instead of your own in house-original-cooked bricks. Ok, making your own bricks give you more control over the final result and the way you work with them, but after building two or three houses, you realize it is very cumbersome and time consuming, and not really practical for a "real world" builder... Although making your own bricks could make sense if instead of being a house builder, you are a bricks vendor. It is the same with programming languages: If you are planning to write the next operating system, or a database management system to be used in mission critical applications by millions of users, or perhaps a 3D graphics application, you'd better use C. Fort anything else, boy, don't lose your time. Use Python, get the job done with the least delay and have fun. My two cents... Luis On 20 jul, 19:50, [EMAIL PROTECTED] wrote: > I'm just learning about Python now and it sounds interesting. But I > just read (on the Wiki page) that mainstream Python was written in C. > That's what I was searching for: Python was written in what other > language? > > See, my concern was something like: OK, if Python is so hot, then, > hopefully someone is writing it in assembly language for each MPU chip > out there. Otherwise, if, say, they've written it in C#, then it looks > like the REAL, generally useful language to learn is C# and Python is > akin to Visual Basic or something: a specialty languagewhereas > REAL WORLD programmers who want to be generally useful go and learn > C#. > > So I was suspecting the Python compiler or interpreter is written in a -- http://mail.python.org/mailman/listinfo/python-list
persistent deque (continued)
Some time ago, I was asking about the feasibility of a persistent deque, a double-ended queue. It runs into the typical space allocation problems. If you're storing a pickle, you have to allocate and fragment the file you've opened, since pickles can be variable-length strings; i.e. if the new data is too long, blank out its entry, and grow the file. If you're storing a data-type, you lose Python's dynamic-type advantages, as well as its long integers, as they can be any length. If you change the object in the deque, such as when using any mutable type, you have to update the container too. Does anyone have any experience storing pickles (I am aware of the similarities to shelf) to a database? Can the file system facilitate the variable-length string problem? How feasible is a length-of-length - length - data solution to the unbounded integer problem? Is there any alternative to completely re-pickling a large (say 1k pickled) object you only change slightly? What other issues are there? Is a hybrid-storage type possible, that stores the contents of its Python-allocated memory block to disk, including reference count, even if it's a lot slower? The object could not contain any references to objects not allocated on disk. A first approach is for the file to look like this: 00 data 01 data 02 01 data 03 data 04 02 data 05 data 06 Append would add: 03 data 07 data 08 AppendLeft would add: -01 data 09 data 0a Pop would remove 03, PopLeft would remove -01. You would need a length-and-head index to make 'rotate' available. Remove would run a worst-case risk of renumbering half of the indices stored, plus a rotate. -- http://mail.python.org/mailman/listinfo/python-list
Converting List of String to Integer
Hi Everyone, I am relatively new to Python so please forgive me for what seems like a basic question. Assume that I have a list, a, composed of nested lists with string representations of integers, such that a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']] I would like to convert this to a similar list, b, where the values are represented by integers, such as b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]] I have unsuccessfully tried the following code: n = [] for k in a: n.append([int(v) for v in k]) print n Does anyone know what I am doing wrong? Thanks in advance. Samir -- http://mail.python.org/mailman/listinfo/python-list
Re: scanf in python
AMD schrieb: Hello, I often need to parse strings which contain a mix of characters, integers and floats, the C-language scanf function is very practical for this purpose. I've been looking for such a feature and I have been quite surprised to find that it has been discussed as far back as 2001 but never implemented. The recommended approach seems to be to use split and then atoi or atof or to use regex and then atoi and atof. Both approaches seem to be a lot less natural and much more cumbersome than scanf. If python already has a % string operator that behaves like printf, why not implement either a %% or << string operator to behave like scanf, use could be like the followng: a, b, c = "%d %f %5c" %% "1 2.0 abcde" or a, b, c = "%d %f %5c" << "1 2.0 abcde" %% is closer to the % operator << seems more intuitive to me either of this methods seems to me much simpler than: lst = "1 2;0 abcde".split() a = int(lst[0]) b = float(lst[1]) c = lst[2] or even worse when using regular expressions to parse such simple input. I like python because it is concise and easy to read and I really think it could use such an operator. I know this has been discussed before and many times, but all previous threads I found seem to be dead and I would like to invite further investigation of this topic. I'm pretty certain python won't grow an additional operator for this. Yet you are free to create a scanf-implementation as 3rd-party-module. IMHO the usability of the approach is very limited though. First of all, the need to capture more than one input token is *very* seldom - nearly all commandline-tools I know that do require interactive user-input (like the linux kernel config tool) do so by providing either line-by-line value entry (including defaults, something you can't do with your approach), or even dialog-centric value entry with curses. So - I doubt you will gather much momentum on this. Good luck though. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: interpreter vs. compiled
On Jul 18, 2:13 pm, Dan <[EMAIL PROTECTED]> wrote:
> On Jul 18, 2:17 pm, castironpi <[EMAIL PROTECTED]> wrote:
>
>
>
> > On Jul 17, 11:39 pm, Kay Schluehr <[EMAIL PROTECTED]> wrote:
>
> > > On 18 Jul., 01:15, castironpi <[EMAIL PROTECTED]> wrote:
>
> > > > On Jul 17, 5:37 pm, I V <[EMAIL PROTECTED]> wrote:
>
> > > > > On Thu, 17 Jul 2008 15:08:17 -0700, castironpi wrote:
> > > > > > The Python disassembly is baffling though.
>
> > > > > y= 3
> > > > > dis.dis('x=y+1')
>
> > > > > You can't disassemble strings of python source (well, you can, but, as
> > > > > you've seen, the results are not meaningful). You need to compile the
> > > > > source first:
>
> > > > > >>> code = compile('y=x+1','-', 'single')
> > > > > >>> dis.dis(code)
>
> > > > > 1 0 LOAD_NAME 0 (x)
> > > > > 3 LOAD_CONST 0 (1)
> > > > > 6 BINARY_ADD
> > > > > 7 STORE_NAME 1 (y)
> > > > > 10 LOAD_CONST 1 (None)
> > > > > 13 RETURN_VALUE
>
> > > > > You may well find these byte codes more meaningful. Note that there
> > > > > is a
> > > > > list of opcodes athttp://docs.python.org/lib/bytecodes.html
>
> > > > Oh. How is the stack represented?
>
> > > As a pointer to a pointer of PyObject structs.
>
> > > > Does it keep track of which stack
> > > > positions (TOS, TOS1, etc.) are in what registers? Does stack
> > > > manipulation consume processor cycles?
>
> > > Python does not store values in registers. It stores locals in arrays
> > > and accesses them by position ( you can see the positional index in
> > > the disassembly right after the opcode name ) and globals / object
> > > attributes in dicts.
>
> > > For more information you might just download the source distribution
> > > and look for src/Python/ceval.c. This file contains the main
> > > interpreter loop.
>
> > Ah, found it. The parts that are making sense are:
>
> > register PyObject **stack_pointer;
> > #define TOP() (stack_pointer[-1])
> > #define BASIC_POP() (*--stack_pointer)
>
> > ...(line 1159)...
> > w = POP();
> > v = TOP();
> > if (PyInt_CheckExact(v) && PyInt_CheckExact(w)) {
> > /* INLINE: int + int */
> > register long a, b, i;
> > a = PyInt_AS_LONG(v);
> > b = PyInt_AS_LONG(w);
> > i = a + b;
> > if ((i^a) < 0 && (i^b) < 0)
> > goto slow_add;
> > x = PyInt_FromLong(i);
>
> > ... Which is more than I was picturing was involved. I understand it
> > is also specific to CPython. Thanks for the pointer to the code.
>
> > My basic question was, what is the difference between compilers and
> > interpreters, and why are interpreters slow? I'm looking at some of
> > the answer right now in "case BINARY_ADD:".
>
> The basic difference between a (traditional) compiler and an
> interpreter is that a compiler emits (assembly) code for a specific
> machine. Therefore it must know the specifics of the machine (how many
> registers, memory addressing modes, etc), whereas interpreters
> normally define themselves by their conceptual state, that is, a
> virtual machine. The instructions (bytecode) of the virtual machine
> are generally more high-level than real machine instructions, and the
> semantics of the bytecode are implemented by the interpreter, usually
> in a sort-of high level language like C. This means the interpreter
> can run without detailed knowledge of the machine as long as a C
> compiler exists. However, the trade off is that the interpreter
> semantics are not optimized for that machine.
>
> This all gets a little more hairy when you start talking about JITs,
> runtime optimizations, and the like. For a real in-depth look at the
> general topic of interpretation and virtual machines, I'd recommend
> Virtual Machines by Smith and Nair (ISBN:1-55860910-5).
>
> -Dan
You're saying the VM can't compile code. That makes sense, it's not a
compiler. Do I understand correctly that JIT does compile to native
code in some cases?
Python: x= y+ 1
Python VM: push, push, add, store
Assembly: load, load, add, store
Except, the assembly doesn't contain the type-checking that
PyInt_AS_LONG does. But that's not the only thing that stops python
from precompiling to assembly directly. GNU doesn't come with
Python. What sorts of minimal information would be necessary to take
from the GNU libs for the user's specific processor, (the one they're
downloading their version of Python for), to move Python to the
further step of outputting the machine code?
--
http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Jul 20, 11:59 pm, Michael Torrie <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] wrote: > > I'm not dissing Python, here. Just noting that, if it is written in C, > > that throws a curve at me in trying to balance the value of learning > > Python vs. some other major language. > > Definitely one of the most non-sequitor statements I have ever heard. > Actually your entire post doesn't make much sense. Maybe you are a > brother bot to castropini? Perhaps a less-trained one, although none of > castropini's posts seem to make sense either. The AI needs a bit of work. Are you saying Python is not good for writing A.I., or the A.I. isn't good at writing Python? -- http://mail.python.org/mailman/listinfo/python-list
Re: automating python programs
On Mon, Jul 21, 2008 at 2:12 PM, Zach Hobesh <[EMAIL PROTECTED]> wrote: > Hi, > > I'm trying to figure out how to run a python program on a schedule, maybe > every half an hour... Is this possible? > > Thanks! > > -Zach > > -- > http://mail.python.org/mailman/listinfo/python-list > On Linux, man cron. -- http://mail.python.org/mailman/listinfo/python-list
RE: automating python programs
Windows scheduler is one of the option. From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Zach Hobesh Sent: Monday, July 21, 2008 2:13 PM To: python-list@python.org Subject: automating python programs Hi, I'm trying to figure out how to run a python program on a schedule, maybe every half an hour... Is this possible? Thanks! -Zach -- http://mail.python.org/mailman/listinfo/python-list
Re: calling source command within python
On Mon, Jul 21, 2008 at 1:59 PM, mk <[EMAIL PROTECTED]> wrote:
> Jie wrote:
>
>> Hi all,
>>
>> i'm having trouble executing os.system('source .bashrc') command
>> within python, it always says that source not found and stuff. Any
>> clue?
>>
>
> It _might_ be that the shell it fires up is /bin/sh and this in turn is not
> bash.
>
> Anyway, it's better to use subprocess / Popen for this sort of operation.
>
>
>
"source" is a bash built-in command and not an executable file. That's why
you need to do something like execute "/bin/bash .bashrc".
--
http://mail.python.org/mailman/listinfo/python-list
automating python programs
Hi, I'm trying to figure out how to run a python program on a schedule, maybe every half an hour... Is this possible? Thanks! -Zach -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Mon, Jul 21, 2008 at 1:21 PM, Marc 'BlackJack' Rintsch
<[EMAIL PROTECTED]> wrote:
> On Mon, 21 Jul 2008 18:12:54 +0200, mk wrote:
>
>> Seriously, though, would there be any advantage in re-implementing
>> Python in e.g. C++?
>>
>> Not that current implementation is bad, anything but, but if you're not
>> careful, the fact that lists are implemented as C arrays can bite your
>> rear from time to time (it recently bit mine while using lxml). Suppose
>> C++ re-implementation used some other data structure (like linked list,
>> possibly with twists like having an array containing pointers to 1st
>> linked list elements to speed lookups up), which would be a bit slower
>> on average perhaps, but it would behave better re deletion?
Aside (actual reply below): at least for a sorted LL, you're basically
describing Henriksen's algorithm. They can asymptotically be faster,
based on amortized analysis, but they're somewhat more complicated to
implement.
>
> An operation that most people avoid because of the penalty of "shifting
> down" all elements after the deleted one. Pythonistas tend to build new
> lists without unwanted elements instead. I can't even remember when I
> deleted something from a list in the past.
>
> Ciao,
>Marc 'BlackJack' Rintsch
The other side of the equation though is the OO-overhead for C++
programs as compared to C. (A couple years ago we used an
instrumentation tool to check the instruction count for a simple hello
world program written in C (ie, main(){printf("Hello world!"); return
0;}) and Python (main(){cout<<"hello world"
Re: Almost keywords
[EMAIL PROTECTED] wrote: > A possible way to avoid such bugs is to turn all those names like > "list", "map", "filter", "self", etc into keywords. But this may have > some disadvantages (well, I think I'd like to have "self" as keyword, > seen how all Python books strong suggest to not use a name different > from "self"). I'm not convinced by making 'self' a keyword. Forcing the first argument of a method to be named 'self' fails for many reasons (e.g. classmethod/staticmethod) so I don't really see a benefit to making it special in any way. For the other names though, this would have the advantage of allowing the compiler to optimise access to builtins which should provide a slight speed improvement and I think would also make life easier for some implementations (especially things like 'locals()'). A half-way house would be to generate a warning for any use of a name which masks one of the reserved builtins, but only optimise lookups in scopes where no such masking is seen by the compiler: this would prevent you overriding builtins by injecting a name into the global namespace from outside a module but not otherwise break existing code. Of course any of this would break some existing code and therefore isn't going to happen. -- http://mail.python.org/mailman/listinfo/python-list
Re: calling source command within python
Jie wrote:
Hi all,
i'm having trouble executing os.system('source .bashrc') command
within python, it always says that source not found and stuff. Any
clue?
It _might_ be that the shell it fires up is /bin/sh and this in turn is
not bash.
Anyway, it's better to use subprocess / Popen for this sort of operation.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Error importing modules with mod_python
Aaron Scott wrote: > I've installed mod_python, and everything seems to be working, but it > fails when I try to import another file into the file that's actually > producing the output. I have these lines at the top of index.py: > > from mod_python import apache > from storylab import * > > ... and in the directory where index.py resides (/htdocs/python/), I > have a directory called "storylab". Inside that directory is > __init__.py. When I try to execute /htdocs/python/index.py, I get the > following error: > > --- > > MOD_PYTHON ERROR > ProcessId: 828 > Interpreter:'localhost' > ServerName: 'localhost' > DocumentRoot: 'C:/htdocs' > URI:'/python/index.py' > Location: None > Directory: 'C:/htdocs/python/' > Filename: 'C:/htdocs/python/index.py' > PathInfo: '' > Phase: 'PythonHandler' > Handler:'index' > > Traceback (most recent call last): > > File "C:\Python25\lib\site-packages\mod_python\importer.py", line > 1537, in HandlerDispatch > default=default_handler, arg=req, silent=hlist.silent) > > File "C:\Python25\lib\site-packages\mod_python\importer.py", line > 1202, in _process_target > module = import_module(module_name, path=path) > > File "C:\Python25\lib\site-packages\mod_python\importer.py", line > 296, in import_module > log, import_path) > > File "C:\Python25\lib\site-packages\mod_python\importer.py", line > 680, in import_module > execfile(file, module.__dict__) > > File "C:\htdocs\python\index.py", line 2, in > from storylab import * > > ImportError: No module named storylab > > --- > > What am I doing wrong? Any insight would be greatly appreciated. You need to tell python that it should add the path your storylab-module is residing in to the sys.path-list of module locations. There are a bunch of ways to do so: - in your main-script, import sys, and append the proper path to sys.path - add a .pth-file into python's site-packages that points to the location - set the environment variable PYTHONPATH - use distutils or setuptools to proper install the module. Google will help you to find additional information about the above mentioned concepts. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: Seriously, though, about LLVM
Fredrik Lundh wrote: mk wrote: This project has gained some publicity. There's IronPython, right, so has anybody thought about implementing Python using LLVM as backend, as it seems not out of question at all? you mean like: http://llvm.org/ProjectsWithLLVM/#pypy ? No, I don't mean "Python written in Python", with whatever backend. -- http://mail.python.org/mailman/listinfo/python-list
Error importing modules with mod_python
I've installed mod_python, and everything seems to be working, but it fails when I try to import another file into the file that's actually producing the output. I have these lines at the top of index.py: from mod_python import apache from storylab import * ... and in the directory where index.py resides (/htdocs/python/), I have a directory called "storylab". Inside that directory is __init__.py. When I try to execute /htdocs/python/index.py, I get the following error: --- MOD_PYTHON ERROR ProcessId: 828 Interpreter:'localhost' ServerName: 'localhost' DocumentRoot: 'C:/htdocs' URI:'/python/index.py' Location: None Directory: 'C:/htdocs/python/' Filename: 'C:/htdocs/python/index.py' PathInfo: '' Phase: 'PythonHandler' Handler:'index' Traceback (most recent call last): File "C:\Python25\lib\site-packages\mod_python\importer.py", line 1537, in HandlerDispatch default=default_handler, arg=req, silent=hlist.silent) File "C:\Python25\lib\site-packages\mod_python\importer.py", line 1202, in _process_target module = import_module(module_name, path=path) File "C:\Python25\lib\site-packages\mod_python\importer.py", line 296, in import_module log, import_path) File "C:\Python25\lib\site-packages\mod_python\importer.py", line 680, in import_module execfile(file, module.__dict__) File "C:\htdocs\python\index.py", line 2, in from storylab import * ImportError: No module named storylab --- What am I doing wrong? Any insight would be greatly appreciated. Thanks, Aaron -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Mon, 21 Jul 2008 18:12:54 +0200, mk wrote: > Seriously, though, would there be any advantage in re-implementing > Python in e.g. C++? > > Not that current implementation is bad, anything but, but if you're not > careful, the fact that lists are implemented as C arrays can bite your > rear from time to time (it recently bit mine while using lxml). Suppose > C++ re-implementation used some other data structure (like linked list, > possibly with twists like having an array containing pointers to 1st > linked list elements to speed lookups up), which would be a bit slower > on average perhaps, but it would behave better re deletion? An operation that most people avoid because of the penalty of "shifting down" all elements after the deleted one. Pythonistas tend to build new lists without unwanted elements instead. I can't even remember when I deleted something from a list in the past. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
In article <[EMAIL PROTECTED]>, Erik Max Francis <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] wrote: > > > I'm just learning about Python now and it sounds interesting. But I > > just read (on the Wiki page) that mainstream Python was written in C. > > That's what I was searching for: Python was written in what other > > language? > > > > See, my concern was something like: OK, if Python is so hot, then, > > hopefully someone is writing it in assembly language for each MPU chip > > out there. Otherwise, if, say, they've written it in C#, then it looks > > like the REAL, generally useful language to learn is C# and Python is > > akin to Visual Basic or something: a specialty languagewhereas > > REAL WORLD programmers who want to be generally useful go and learn > > C#. > > Psst. What language do you think the primary implementations of C# is > written in? I know, I know, call on me! Object Pascal, obviously. -- David C. Ullrich -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Written in C?
On Mon, 21 Jul 2008 17:06:03 +0100, Tim Golden wrote: > mk wrote: > >> Wrong! Real programmers can program using only Touring machine > > Is that some kind of bicycle? Maybe it's a Turing machine after Bicycle Repair Man got his hands on it!? Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: how to create GUI dynamically
On Jul 21, 8:19 am, [EMAIL PROTECTED] wrote: > Hi; > > i m working on a project where i need run time creation of GUI. > > i have some no. of entities for which i want checkboxes in front of > them which can be checked/ unchecked by user. > > But the problem is that the number and name of entities is not fixed > and it depends on the file which is used as input. > > So is there any way to tackle this problem. > > By the way ; i use Boa constructor (zope editor) for GUI now. > > regards > pawan pundir You should check out Traits and Traits UI: http://code.enthought.com/projects/traits/examples.php It allows you to dynamically create views and UIs in an easy, declarative manner. It is also powerful enough to build much more complex interactions and dialogs. It currently supports both WX and Qt toolkits. -Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: how to create GUI dynamically
[EMAIL PROTECTED] wrote: Hi; i m working on a project where i need run time creation of GUI. i have some no. of entities for which i want checkboxes in front of them which can be checked/ unchecked by user. But the problem is that the number and name of entities is not fixed and it depends on the file which is used as input. So is there any way to tackle this problem. By the way ; i use Boa constructor (zope editor) for GUI now. regards pawan pundir All the GUI tookits (Tkinter, wxWindows, QT) allow you to build the GUI dynamically. -Larry -- http://mail.python.org/mailman/listinfo/python-list
Re: Please recommend a RPC system working with twisted.
??? wrote: Hi all, I'm looking for an RPC system working with twisted. 1. Binary. I want it run faster than any xml based RPC. 2. Bidirectional. Unlike HTTP, on which the client has to poll the sever for events, the server should "call" the client's method to notify events. 3. C/Python support. Part of the system shall be written in C. 4. Could easily integrated with twisted. Unfortunately, there seems no such resolution existed. So maybe I have to give up some requirements. --- It would be wonderful if ICE could integrate with twisted! Twisted Perspective Broker? -Larry -- http://mail.python.org/mailman/listinfo/python-list
scanf in python
Hello, I often need to parse strings which contain a mix of characters, integers and floats, the C-language scanf function is very practical for this purpose. I've been looking for such a feature and I have been quite surprised to find that it has been discussed as far back as 2001 but never implemented. The recommended approach seems to be to use split and then atoi or atof or to use regex and then atoi and atof. Both approaches seem to be a lot less natural and much more cumbersome than scanf. If python already has a % string operator that behaves like printf, why not implement either a %% or << string operator to behave like scanf, use could be like the followng: a, b, c = "%d %f %5c" %% "1 2.0 abcde" or a, b, c = "%d %f %5c" << "1 2.0 abcde" %% is closer to the % operator << seems more intuitive to me either of this methods seems to me much simpler than: lst = "1 2;0 abcde".split() a = int(lst[0]) b = float(lst[1]) c = lst[2] or even worse when using regular expressions to parse such simple input. I like python because it is concise and easy to read and I really think it could use such an operator. I know this has been discussed before and many times, but all previous threads I found seem to be dead and I would like to invite further investigation of this topic. Cheers, André M. Descombes -- http://mail.python.org/mailman/listinfo/python-list
Re: Change PC to Win or Windows
On Sat, Jul 19, 2008 at 02:56:07AM -0700, Lie wrote: > government, etc. IBM PC is one of the first computers that ordinary > people could possess, when IBM-clones appeared on the market, they're > referred as PCs too because they are Personal Computer, a computer > that is designed for personal use. Just to be clear, this statement is WRONG. PC-clones were so called because they were clones of the IBM-PC. The term is very specific to IBM-compatible hardware. http://en.wikipedia.org/wiki/Pc_clone IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC, XT, or AT internal design, facilitated by various manufacturers' ability to legally reverse engineer the BIOS through cleanroom design. Wikipedia's article on the personal computer accurately reflects the multiple meanings of the term, and points out the common usage to mean a Windows box: http://en.wikipedia.org/wiki/Personal_computer Today a PC may be a desktop computer, a laptop computer or a tablet computer. The most common operating systems are Microsoft Windows, Mac OS X and Linux, while the most common microprocessors are x86 compatible CPUs. However, the term "PC" is often used only to refer to computers running Microsoft Windows. So please stop your whining and get used to the idea that THE REST OF THE WORLD uses PC to mean a Windows box. -- Derek D. Martin http://www.pizzashack.org/ GPG Key ID: 0x81CFE75D pgpWskQ7X4hnX.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Run as Service
[EMAIL PROTECTED] wrote: I have, in the past, used SRVANY to run a Python app as a Windows service. However, now I am interested in distributing my scripts and want to make it as painless for the end user as possible (hands-off is best :). How can you go about running a Python app as a Windows service without SRVANY? Pick up a copy of Mark Hammond's book "Python on Win32". It has an excellent chapter on using Win32 extensions to write Windows Services. Also you might consider looking at gmane.comp.python.windows usergroup. -Larry -- http://mail.python.org/mailman/listinfo/python-list
