ANN: Amara XML Toolkit 1.0b2
http://uche.ogbuji.net/tech/4Suite/amara ftp://ftp.4suite.org/pub/Amara/ Changes in this release: * More mutation API improvements (del and assignment can now be used with elements as well as attributes) [1][2][3] * Slight improvements in 4Suite XSLT compatability (still some remaining issues) * Bug fixes [1] http://copia.ogbuji.net/blog/2005-04-17/Amara_gets [2] http://copia.ogbuji.net/blog/2005-04-18/Elements_v [3] http://copia.ogbuji.net/blog/2005-04-18/Deletion_a Amara XML Toolkit is a collection of Python tools for XML processing-- not just tools that happen to be written in Python, but tools built from the ground up to use Python idioms and take advantage of the many advantages of Python. Amara builds on 4Suite [http://4Suite.org], but whereas 4Suite focuses more on literal implementation of XML standards in Python, Amara focuses on Pythonic idiom. It provides tools you can trust to conform with XML standards without losing the familiar Python feel. The components of Amara are: * Bindery: data binding tool (a very Pythonic XML API) * Scimitar: implementation of the ISO Schematron schema language for XML; converts Schematron files to Python scripts * domtools: set of tools to augment Python DOMs * saxtools: set of tools to make SAX easier to use in Python * Flextyper: user-defined datatypes in Python for XML processing There's a lot in Amara, but here are highlights: Amara Bindery: XML as easy as py Bindery turns an XML document into a tree of Python objects corresponding to the vocabulary used in the XML document, for maximum clarity. For example, the document monty python spam=eggsWhat do you mean bleh/python python ministry=abuseBut I was looking for argument/python /monty Becomes a data structure such that you can write binding.monty.python.spam In order to get the value eggs or binding.monty.python[1] In order to get the value But I was looking for argument. There are other such tools for Python, and what makes Anobind unique is that it's driven by a very declarative rules-based system for binding XML to the Python data. You can register rules that are triggered by XPattern expressions specialized binding behavior. It includes XPath support and supports mutation. Bindery is very efficient, using SAX to generate bindings. Scimitar: Schematron for Pytthon Merged in from a separate project, Scimitar is an implementation of ISO Schematron that compiles a Schematron schema into a Python validator script. You typically use scimitar in two phases. Say you have a schematron schema schema1.stron and you want to validate multiple XML files against it, instance1.xml, instance2.xml, instance3.xml. First you run schema1.stron through the scimitar compiler script, scimitar.py: scimitar.py schema1.stron The generated file, schema1.py, can be used to validate XML instances: python schema1.py instance1.xml Which emits a validation report. Amara DOM Tools: giving DOM a more Pythonic face DOM came from the Java world, hardly the most Pythonic API possible. Some DOM-like implementations such as 4Suite's Domlettes mix in some Pythonic idiom. Amara DOM Tools goes even further. Amara DOM Tools feature pushdom, similar to xml.dom.pulldom, but easier to use. It also includes Python generator-based tools for DOM processing, and a function to return an XPath location for any DOM node. Amara SAX Tools: SAX without the brain explosion Tenorsax (amara.saxtools.tenorsax) is a framework for linerarizing SAX logic so that it flows more naturally, and needs a lot less state machine wizardry. License --- Amara is open source, provided under the 4Suite variant of the Apache license. See the file COPYING for details. Installation Amara requires Python 2.3 or more recent and 4Suite 1.0a4 or more recent. Make sure these are installed, unpack Amara to a convenient location and run python setup.py install -- Uche Ogbuji Fourthought, Inc. http://uche.ogbuji.nethttp://fourthought.com http://copia.ogbuji.net http://4Suite.org Use CSS to display XML, part 2 - http://www-128.ibm.com/developerworks/edu/x-dw-x-xmlcss2-i.html Writing and Reading XML with XIST - http://www.xml.com/pub/a/2005/03/16/py-xml.html Use XSLT to prepare XML for import into OpenOffice Calc - http://www.ibm.com/developerworks/xml/library/x-oocalc/ Schema standardization for top-down semantic transparency - http://www-128.ibm.com/developerworks/xml/library/x-think31.html -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Re: Why Python does *SLICING* the way it does??
Op 2005-04-20, Bill Mill schreef [EMAIL PROTECTED]: On 20 Apr 2005 13:39:42 GMT, Antoon Pardon [EMAIL PROTECTED] wrote: Op 2005-04-20, Bill Mill schreef [EMAIL PROTECTED]: You write this af if other solutions can't be consistent. Propose one, and I won't write it off without thinking, but my bias is way against it from experience. Knowledge gets scattered across the program, Knowledge always gets scattered across the program. The end index can vary endlessly but that doesn't seem to worry you. So why is a varying start index so worrysome? unless you're defining the start index every time you use the list, which seems no better than adding an offset to me. I don't see why the start index can't be accessible through a method or function just like the length of a list is now. My favourite would be a range method so we would have the following idiom: for i in lst.range(): do something with lst[i] -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Op 2005-04-20, Roy Smith schreef [EMAIL PROTECTED]: Antoon Pardon [EMAIL PROTECTED] wrote: Op 2005-04-20, Roy Smith schreef [EMAIL PROTECTED]: Antoon Pardon [EMAIL PROTECTED] wrote: Personnaly I would like to have the choice. Sometimes I prefer to start at 0, sometimes at 1 and other times at -13 or +7. Argggh. Having two (or more!) ways to do it, would mean that every time I read somebody else's code, I would have to figure out which flavor they are using before I could understand what their code meant. That would be evil. This is nonsens. table[i] = j, just associates value j with key i. That is the same independend from whether the keys can start from 0 or some other value. Do you also consider it more ways because the keys can end in different values? There are certainly many examples where the specific value of the first key makes no difference. A good example would be for element in myList: print element On the other hand, what output does myList = [spam, eggs, bacon] print myList[1] produce? In a language where some lists start with 0 and some start with 1, I don't have enough information just by looking at the above code. Yes you have. The fact that a language allows a choice doesn't contradict there is a default, when no choice is specified. My preference would be that it would produce spam, because if you want the *first* element, you want the element associated withe the key 1. Or maybe the language would force you to give a start index, so that you would have to write: MyList = [3 - spam, eggs, bacon] End of course the language would provide instances or methods so you could ask what the first index was. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
[EMAIL PROTECTED] wrote: What languages besides Python use the Python slicing convention? Java uses it for the substring method of strings. In C starting at 0 may be justified because of the connection between array subscripting and pointer arithmetic, but Python is a higher-level language where such considerations are less relevant. Maybe less relevant, but relevant nonetheless. First, there's the desire for familiarity. Many Python programmers are also C programmers, and that fact has had an influence on the development of the language. That's why we write x += 0x20 rather than x := x + $20. Why not array indexing as well? More importantly, there are reasons for counting from zero that have nothing to do with pointers. The biggest reason involves modular arithmetic: r=n%d satifies 0 = r d, which conveniently matches Python's array syntax. DAY_NAMES = [Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday] def weekday_name(date): return DAY_NAMES[date.toordinal() % 7] Modular arithmetic's preference for 0-based counting goes beyond array indexing. For example, consider our notation for time, from 00:00:00 to 23:59:59. def time_add(time, delta): time = an (hour, minute, second) tuple for a time of day delta = an (hour, minute, second) tuple for an amount of time Returns time+delta, as an (hour, minute, second) tuple. hour = time[0] + delta[0] minute = time[1] + delta[1] second = time[2] + delta[2] # Normalize the time second = ((hour * 60) + minute) * 60 + second minute, second = divmod(second, 60) hour, minute = divmod(minute, 60) hour %= 24 return hour, minute, second Imagine that the time notation went from 01:01:01 to 24:60:60. Try writing a time_add function for that. The only simple way I can think of is to temporarily convert to zero-based notation! def time_add(time, delta): # Add like terms and convert to zero-based notation. hour = time[0] + delta[0] - 1 minute = time[1] + delta[1] - 1 second = time[2] + delta[2] - 1 # Normalize the time second = ((hour * 60) + minute) * 60 + second minute, second = divmod(second, 60) hour, minute = divmod(minute, 60) hour %= 24 # Convert back to one-based notation on output return hour + 1, minute + 1, second + 1 Along the same lines, I think the REQUIREMENT that x[0] rather than x[1] be the first element of list x is a mistake. At least the programmer should have a choice, as in Fortran or VBA. If you really want 1-based arrays, just do what most BASIC programmers do: Ignore x[0]. months = [None, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec] print months[4] Apr -- http://mail.python.org/mailman/listinfo/python-list
regarding main function
Dear All, I want to know the difference between calling a function directly and through main function compose() if __name__ == __main__: compose() Yahoo! India Matrimony: Find your life partner online Go to: http://yahoo.shaadi.com/india-matrimony -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Op 2005-04-20, Peter Hansen schreef [EMAIL PROTECTED]: Terry Hancock wrote: However, I used to make off by one errors all the time in both C and Fortran, whereas I hardly ever make them in Python. This should probably be the overriding concern in this case. I can't remember the last time I made an off-by-one error in Python (or, really, whether I ever have), whereas I can't remember the last C program I wrote which didn't have one. I do so frequently. I often have to process files where each line is a record, each record having a number of fields seperated with a delimiter. So the idiom for treating such files has become for line in the_file: lst = line.split(delimiter) The problem is that the fields in lst are associated with a number that is off by one as they are normally counted. If I go and ask my colleague which field contains some specific data and he answers: the 5th, I have to remind my self I want lst[4] This is often a cause for errors. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Op 2005-04-20, Terry Hancock schreef [EMAIL PROTECTED]: On Wednesday 20 April 2005 07:52 am, Antoon Pardon wrote: Personnaly I would like to have the choice. Sometimes I prefer to start at 0, sometimes at 1 and other times at -13 or +7. Although I would classify that as a rare use case. So, it ought to be possible to do it, but not necessarily easy. The -13 and +7 may be rare cases, but I wouldn't call one as a start index a rare case. I often get data in files where each line is a record with delimited fields. When I ask which field contains certain data, I get an answer that depends on counting starting with one. So starting with one as index would seem the more natural choice here. As far as I'm concerend, 0 as a starting index is a rare use case. In the programs I write about 45% is a natural 1 for first index, about 50% is a don't care and 5% is a natural 0 first index and some fraction is others. So yes in most of my programs 0 as a starting index works fine, but that is because in a lot of programs it doesn't matter much which would be the first index. Now I can understand that for others the 0 as a natural start index is more frequent, but if we have two frequent use cases, it seems to me the language should provide the choice more easily as it does now. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
[Antoon Pardon] I don't see why the start index can't be accessible through a method or function just like the length of a list is now. My favourite would be a range method so we would have the following idiom: for i in lst.range(): do something with lst[i] After going to all that trouble, you might as well also get the value at that position: for i, x in enumerate(lst): do something with lst[i] also known as x Raymond Hettinger -- http://mail.python.org/mailman/listinfo/python-list
Re: regarding main function
if you run in the same file there is no difference. Block under __main__ will be executed if you run that file only but if you import that file from another file, then if you don't put your code inside __main__ your code it will be executed (this is not what you want). Example: You have 1 file called mydll.py inside mydll you have : def func1(): print 'Helo world' # you want to test your func1() func1() # when you run you get 'Helo world' then you have another file called MyCode.py which you like to call func1(), inside this file you have this code: import mydll mydll.func1() # you hope you get 'Helo World' # In fact you get : # 'Helo World' # 'Helo World' -- This happened because when you import mydll python will execute all code in mydll including the one you put it for test. So to overcome this problem if you want to test your code put inside block __main__, next time you import your mydll it won't execute any codes inside __main__ Hope this help. Pujo -- http://mail.python.org/mailman/listinfo/python-list
Re: PyObject_New not running tp_new for iterators?
I wrote: [snip] What am I missing? The fundamental problem is that this: if (!(ro = PyObject_New(MyIter, MyIterType))) return NULL; is really only a malloc() - it doesn't call the tp_new function at all. This is not really clear in the 2.3 version of the C API document that I was consulting - the 2.4 version is much clearer. I have no idea how to do in C all the things that calling a class constructor in Python does. Am I supposed to be calling tp_new tp_init directly? In the end, this particular class really only needs to be created from a factory function, so I removed the tp_new member altogether and just wrote a C function to initialise the object, and called that from the C factory function. [The above is not particular to the fact that my class is an iterator - all C classes have the same behaviour. My test of a plain-old class probably looked like it worked due to lucky memory patterns.] -- http://mail.python.org/mailman/listinfo/python-list
deprecation of has_key?
I haven't heard of any plans to deprecate the dictionary has_key method, as the in keyword makes it obsolete. i.e. if key in dict: instead of if dict.has_key(): Is there some reason to keep has_key? --Nick -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Op 2005-04-20, Terry Hancock schreef [EMAIL PROTECTED]: On Wednesday 20 April 2005 12:28 pm, Roy Smith wrote: Terry Hancock wrote: I used to make off by one errors all the time in both C and Fortran, whereas I hardly ever make them in Python. Part of the reason may be that most loops over lists involve iterators, both endpoints are mentioned explicitly. C++/STL also uses iterators, but the syntax is repulsive. That's true of course. It's more likely to show up in manipulating lists or strings. And Python provides a much richer environment for processing strings, so one has to deal with explicit indexing much less. But I still think that I make fewer error per instance of dealing with intervals. It's rare that I even have to think about it much when writing such a thing. Negative indexing also helps a lot. I'm anbivallent about negative indexes. It helps a lot, but can be annoying a lot too. IMO it deters from the, its easier to be forgiven than to get permission, style of programming. It happens rather regularly that I need to do some calculations and if the start conditions were good, I get a valid index for a list and otherwise I get an invalid index. From this specification the following seems a natural way to program try: index = calculate(...) lst[index] = ... ... except IndexError ... But of course this doesn't work because a negative index in this case is an invalid index but python allows it. I sometimes think python should have been more explicite here, using a marker for the start-index and end-index, may '^' and '$'. So if you wanted the last element you had to write: lst[$] And for the next to last element: lst[$ - 1] This would make accessing list elements counted from the rear almost just as easy as it is now but wouldn't interfere with the ask forgiveness programming style. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Lex
I NEED HELP!!! -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
[EMAIL PROTECTED] wrote: Many people I know ask why Python does slicing the way it does. Can anyone /please/ give me a good defense/justification??? I'm referring to why mystring[:4] gives me elements 0, 1, 2 and 3 but *NOT* mystring[4] (5th element). Many people don't like idea that 5th element is not invited. (BTW, yes I'm aware of the explanation where slicing is shown to involve slices _between_ elements. This doesn't explain why this is *best* way to do it.) Chris Hi Chris, What I've found is foreword slicing with positive stepping is very convenient for a lot of things. :-) But when you start trying to use reverse steps, it can get tricky. There are actually 4 different ways to slice and dice. So we have a pretty good choice. So the trick is to match the slice method to what you need, and also use the correct index's for that method. Where s = 'abcd' With s[i,j] Foreword slices index, forward steps a, b, c, d i= 0, 1, 2, 3 j= 1, 2, 3, 4 s[0,4] = 'abcd' s[1,3] = 'bc' Foreword slice index (-steps) a, b, c, d i= 0, 1, 2, 3 j= -5, -4, -3, -2 s[3,-5] = 'dcba' s[2,-4] = 'cb' Reverse slice index (+steps) a, b, c, d i= -4, -3, -2, -1 j= 1, 2, 3, 4 s[-4,4] = 'abcd' s[-3,3] = 'bc' Reverse slice index (-steps) a, b, c, d i= -4, -3, -2, -1 j= -5, -4, -3, -2 s[-1,-5] = 'dcba' s[-2,-4] = 'cb' (Maybe this could be made a little more symetrical for Python 3000?) Cheers, Ron_Adam -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Antoon Pardon [EMAIL PROTECTED] writes: I sometimes think python should have been more explicite here, using a marker for the start-index and end-index, may '^' and '$'. So if you wanted the last element you had to write: lst[$] And for the next to last element: lst[$ - 1] I like this. I don't know how many times I've gotten screwed by wanting the n'th element from the last for variable n, and saying lst[n] then realizing I have a bug when n=0. lst[$-n] works perfectly. -- http://mail.python.org/mailman/listinfo/python-list
python LEX
I have to work on python lexical definition in Lex. I spent lots of my time to find regular expresions written for Lex of Python language but nothing. Can somebody help me? I nEED hELP -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Op 2005-04-21, Raymond Hettinger schreef [EMAIL PROTECTED]: [Antoon Pardon] I don't see why the start index can't be accessible through a method or function just like the length of a list is now. My favourite would be a range method so we would have the following idiom: for i in lst.range(): do something with lst[i] After going to all that trouble, you might as well also get the value at that position: for i, x in enumerate(lst): do something with lst[i] also known as x No you wouldn't, enumerate always starts with 0. So if you write a class with list-like behaviour except that the start index can be different from 0, enumerate is useless because lst[i] won't be x in that case. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: (Python newbie) Using XP-SP2/MSVC6: No Python24_d.lib, winzip barfs on Python-2.4.1.tar, cannot download bzip2
Hi Scott, Nice idea. Tried that but no more information about where the file was (not) found (see below). But many thanks for a useful flag. I did not see them in the documentation. What should I be lkooking for? [StopPres: Ah ha -h why did I not think of that?] Bill # installing zipimport hook import zipimport # builtin # installed zipimport hook # C:\Python24\lib\site.pyc matches C:\Python24\lib\site.py import site # precompiled from C:\Python24\lib\site.pyc # C:\Python24\lib\os.pyc matches C:\Python24\lib\os.py import os # precompiled from C:\Python24\lib\os.pyc import nt # builtin # C:\Python24\lib\ntpath.pyc matches C:\Python24\lib\ntpath.py import ntpath # precompiled from C:\Python24\lib\ntpath.pyc # C:\Python24\lib\stat.pyc matches C:\Python24\lib\stat.py import stat # precompiled from C:\Python24\lib\stat.pyc # C:\Python24\lib\UserDict.pyc matches C:\Python24\lib\UserDict.py import UserDict # precompiled from C:\Python24\lib\UserDict.pyc # C:\Python24\lib\copy_reg.pyc matches C:\Python24\lib\copy_reg.py import copy_reg # precompiled from C:\Python24\lib\copy_reg.pyc # C:\Python24\lib\types.pyc matches C:\Python24\lib\types.py import types # precompiled from C:\Python24\lib\types.pyc # C:\Python24\lib\locale.pyc matches C:\Python24\lib\locale.py import locale # precompiled from C:\Python24\lib\locale.pyc import _locale # builtin # C:\Python24\lib\codecs.pyc matches C:\Python24\lib\codecs.py import codecs # precompiled from C:\Python24\lib\codecs.pyc import _codecs # builtin import encodings # directory C:\Python24\lib\encodings # C:\Python24\lib\encodings\__init__.pyc matches C:\Python24\lib\encodings\__ini t__.py import encodings # precompiled from C:\Python24\lib\encodings\__init__.pyc # C:\Python24\lib\encodings\aliases.pyc matches C:\Python24\lib\encodings\aliase s.py import encodings.aliases # precompiled from C:\Python24\lib\encodings\aliases.py c # C:\Python24\lib\encodings\cp1252.pyc matches C:\Python24\lib\encodings\cp1252. py import encodings.cp1252 # precompiled from C:\Python24\lib\encodings\cp1252.pyc # C:\Python24\lib\warnings.pyc matches C:\Python24\lib\warnings.py import warnings # precompiled from C:\Python24\lib\warnings.pyc # C:\Python24\lib\linecache.pyc matches C:\Python24\lib\linecache.py import linecache # precompiled from C:\Python24\lib\linecache.pyc Python 2.4.1 (#65, Mar 30 2005, 09:13:57) [MSC v.1310 32 bit (Intel)] on win32 Type help, copyright, credits or license for more information. import sys # C:\Python24\lib\encodings\cp850.pyc matches C:\Python24\lib\encodings\cp850.py import encodings.cp850 # precompiled from C:\Python24\lib\encodings\cp850.pyc import SHIP Traceback (most recent call last): File stdin, line 1, in ? ImportError: No module named SHIP import SHIP_d Traceback (most recent call last): File stdin, line 1, in ? ImportError: No module named SHIP_d import _SHIP Traceback (most recent call last): File stdin, line 1, in ? ImportError: No module named _SHIP import _SHIP_d Traceback (most recent call last): File stdin, line 1, in ? ImportError: DLL load failed: The specified module could not be found. _SHIP_d Traceback (most recent call last): File stdin, line 1, in ? NameError: name '_SHIP_d' is not defined Scott David Daniels [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Bill Davy wrote: Thanks Jaime, I'm making gradual progress and am finding it quite satisfying. Resorted to tracing Python in MSVC6 to see what it was trying to IMPORT, which is a bit heavy but thank heavens for the sources. You might try running python from a command window and running it -v as in: python -v prog.py -args ... --Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: building a small calculator
[EMAIL PROTECTED] wrote: Thats great info. Thanks. I guess I would know about this if I read through all the manuals, but I'm awefull at reading that kind of stuff. I'll just have to plow through it somehow. Take your time. Feel free to ask questions. Simon Brunning recommended the tutor list - those guys really can help, and it's not like using that list bars you from posting on comp.lang.python. regards Steve -- Steve Holden+1 703 861 4237 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ Python Web Programming http://pydish.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python LEX
jozo wrote: I have to work on python lexical definition in Lex. I spent lots of my time to find regular expresions written for Lex of Python language but nothing. Can somebody help me? I nEED hELP http://systems.cs.uchicago.edu/ply/ -- Tim Daneliuk [EMAIL PROTECTED] PGP Key: http://www.tundraware.com/PGP/ -- http://mail.python.org/mailman/listinfo/python-list
Re: inner sublist positions ?
Bernard A. wrote: maybe have you some better / faster ideas / implementations ? or even a more pythonic to help me learning that You may want to look at string matches algorithm (a good review: [1]). In particular there are classics like Boyer-Moore and some involving minimal automatons similar to your regular expression ideas. [1] http://www-igm.univ-mlv.fr/~lecroq/string/index.html -- http://mail.python.org/mailman/listinfo/python-list
Re: python LEX
Tim Daneliuk wrote: jozo wrote: I have to work on python lexical definition in Lex. I spent lots of my time to find regular expresions written for Lex of Python language but nothing. Can somebody help me? I nEED hELP http://systems.cs.uchicago.edu/ply/ Whoops - I did not read your question carefully enough ... sorry, cannot help with what you actually asked. Slinks off ... -- Tim Daneliuk [EMAIL PROTECTED] PGP Key: http://www.tundraware.com/PGP/ -- http://mail.python.org/mailman/listinfo/python-list
Can an object of a C type have random members added? tp_dictoffset?
One of the cool things about Python is the ability to decorate objects with random extra members: class C: def __init__(self): self.foo = 0 c = C() c.bar = 1 I have a class implemented in C using tp_members to specify (read-only) access to data members in the C struct. I'd like to be able to do the decoration trick with objects of this class. Is this possible? [The documentation for tp_dictoffset eseems to hint that this is possible. how do I use it?] -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
1. comment for debug It can be used in the same way, as the comments for debugging are used, but it will be easier than to use or ''', or using features of text-editors, when it is necessary to comment piece of code which already contains ''' or/and strings already, or there is another #-comments. Using goto, you do not need to edit a code, which is unfamiliar to you. 2. obfuscators goto can be used in the same way, as many of java-obfuscators do Speaking in other words: 1) goto exempts from necessity to install new software (it is critical for remote working, for example, installing X11 may be impossible at all) 2) enables to make new, better software (better obfuscators) -- Best regards, Maxim Kasimov mailto: [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Using Jython in Ant Build Process
On 4/21/05, Maurice LING [EMAIL PROTECTED] wrote: I am looking for a way to use Jython in Ant build process. I have some pure Python scripts (not using any C extensions) that I'll like to incorporate into Java using Jython. I heard that this can be done but you can I set up Ant to do this? Sorry, I'm no expert with Ant. http://www.pycs.net/users/177/stories/11.html -- Cheers, Simon B, [EMAIL PROTECTED], http://www.brunningonline.net/simon/blog/ -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
Reinhold Birkenfeld wrote: John Bokma wrote: Mage wrote: praba kar wrote: Dear All, In Python what is equivalent to goto statement You shouldn't use goto in high-level languages. Nonsense +1 Thank you! Above all your claim is well justified. These brilliant arguments you have put forth really explain in a magnificent way why goto is a sane addition to any HLL. Reinhold OK - Here's some reasoning that may illuminate it. We could, in theory, reduce any language to the minimal Boehm Jacopini control structures (iirc there were only four). In effect, anything beyond these is syntactic sugar. IOW, feel free to use a minimalist Turing Machine to implement your next 100,000 line program. I, on the other hand, have a really hard time finding infinite tapes (in both directions) and a suitably fast tape reader to implement such ideas. (I also seem to recall that any digital circuit can be implemented with nothing more than AND and NOT gates, but I'd rather not, thanks - I don't have enough probes on my oscilloscope to debug that kind of hardware.) Control structures/directives evolve to solve real problems. 'goto', properly used, can actually clarify code, especially when dealing with exceptions and the like. Oh, we may rename it and call it 'break' or 'try/except' or whatever suits the language author's fancy, but the concept is similar, if not identical. 'goto' certainly could be synthesized in Python with the appropriate try/except hierarchy and custom exceptions, but in many cases this would *really* be overkill - a simple 'goto' would be considerably simpler *and* probably easier to understand. Note that I am not arguing for 'goto' in Python, merely trying to respond to your point about why it is does not inherently appropriate for HLLs. Some HLLs almost have to have it by definition. I cut my teeth as programmer writing for embedded realtime systems in a HLL (PL/M). While you could, in theory, completely avoid 'goto' in a realtime environment, it would make all manner of practical programming problems kind of ugly to implement. BTW, all modern systems come complete with 'goto' implemented in *hardware* - they're called interrupts. More to the point, I have seen some really tortured code written in the name of maintaining religious purity of some kind (Structure, Object Orientation,...). While language constructs can promote better- or worse code structuring, at the end of the day, programming is still the expression of human thought. Some people think clearly, some don't, and this has little to do with just what language structures are in use. Python is elegant at almost every level, and I am certainly not arguing for 'goto' in the language. But to reflexively assume that it has *no* place in a modern HLL is, I think, a bit overstated. I must now 'goto' sleep ... and I cannot think of a better way to express this... -- Tim Daneliuk [EMAIL PROTECTED] PGP Key: http://www.tundraware.com/PGP/ -- http://mail.python.org/mailman/listinfo/python-list
Re: pyGTK on Mouse over event ?
the POINTER MOTION MASK doesn't do the trick either. This is the first time i'm using python and pyGTK and it's really sad to see that a simple mouseover is hard to program. :s -- http://mail.python.org/mailman/listinfo/python-list
Re: Enumerating formatting strings
Michael Spencer wrote: Andrew Dalke wrote: I see you assume that only \w+ can fit inside of a %() in a format string. The actual Python code allows anything up to the balanced closed parens. Gah! I guess that torpedoes the regexp approach, then. Thanks for looking at this Michael While Andrew may have found the fatal flaw in your scheme, it's worth pointing out that it works just fine for my original use case. regards Steve -- Steve Holden+1 703 861 4237 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ Python Web Programming http://pydish.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: Python 2.3.2 for PalmOS available
On Tue, 19 Apr 2005 08:03:15 -0700, Lucio Torre wrote: Do you have any experience on PODS? The whole thing is based on Codewarrior and Codewarrior for palm is dead. Nope. Actually, I'm kind of reluctant to use IDEs and it seems PODS is targeted towards Eclipse users; I'd rather use prc-tools since I'm used to the GNU development tools. -- http://mail.python.org/mailman/listinfo/python-list
Re: deprecation of has_key?
[EMAIL PROTECTED] wrote:
I haven't heard of any plans to deprecate the dictionary has_key
method, as the in keyword makes it obsolete.
i.e.
if key in dict:
instead of
if dict.has_key():
Is there some reason to keep has_key?
Two words: backward compatibility. To lose that method now would break
thousands of existing programs. The 2.4 library would probably
experience breakage too ... let's see:
$ find /lib/python2.4/ -name *.py -exec grep has_key {} \; | wc -l
587
Oops!
The method might disappear in Python 3.0, when we will be allowed to
break backward compatibility - you are correct in saying it's no longer
necessary.
regards
Steve
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Re: Python instances
On Wed, 20 Apr 2005 08:33:48 -0400, Kent Johnson [EMAIL PROTECTED] wrote:
[EMAIL PROTECTED] wrote:
Guess i shouldn't think of the __init__(self) function as a constructor
then.
No, that's not it. You shouldn't think of variables defined outside of a
method as instance variables.
In Java for example you can write something like
public class MyClass {
private List list = new ArrayList();
public void add(Object x) {
list.add(x);
}
}
In this case list is a member variable of MyClass instances; 'this' is
implicit in Java.
In Python, if you write something that looks similar, the meaning is different:
class MyClass:
list = []
def add(self, x):
self.list.append(x)
In this case, list is an attribute of the class. The Java equivalent is a
static attribute. In
Python, instance attributes have to be explicitly specified using 'self'. So
instance attributes
have to be bound in an instance method (where 'self' is available):
class MyClass:
def __init__(self):
self.list = []
def add(self, x):
self.list.append(x)
The following shows nothing static anywhere, yet a class has been defined, an
instance created, and
__init__ called with initial value, and the value retrieved as an attribute of
the returned instance,
and it's all an expression.
type('C', (), {'__init__': lambda
self,v:setattr(self,'foo',v)})('hello').foo
'hello'
Regards,
Bengt Richter
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Re: Why Python does *SLICING* the way it does??
[Antoon Pardon] I don't see why the start index can't be accessible through a method or function just like the length of a list is now. My favourite would be a range method so we would have the following idiom: for i in lst.range(): do something with lst[i] After going to all that trouble, you might as well also get the value at that position: for i, x in enumerate(lst): do something with lst[i] also known as x No you wouldn't, enumerate always starts with 0. You don't get it. Your proposed list-like class indicates its start index. enumerate() can be made to detect that start value so that the above code always works for both 0-based and 1-based arrays. Raymond Hettinger -- http://mail.python.org/mailman/listinfo/python-list
Dictionary question.
Hi, I am semi new to Python. Here is my problem : I have a list of 100 random integers. I want to be able to construct a histogram out of the data. So I want to know how many 70's, 71's, etc. I can't figure out how to do this. A dictionary is supposedly can do key value pairs right? I want to be able to see if say 75 is in the data structure, and what its value is, then increment its value as I go through the list finding items. I am sure there is a way to do this. Is a dictionary what I should be using? Thanks for any help. Hope this makes sense, its getting very late here. Regards all. Ed -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Op 2005-04-21, Raymond Hettinger schreef [EMAIL PROTECTED]: [Antoon Pardon] I don't see why the start index can't be accessible through a method or function just like the length of a list is now. My favourite would be a range method so we would have the following idiom: for i in lst.range(): do something with lst[i] After going to all that trouble, you might as well also get the value at that position: for i, x in enumerate(lst): do something with lst[i] also known as x No you wouldn't, enumerate always starts with 0. You don't get it. Your proposed list-like class indicates its start index. enumerate() can be made to detect that start value so that the above code always works for both 0-based and 1-based arrays. Oh you mean if it would be made a buildin class. Personnally I would still prefer my range solution. I often find enumerate gives me too much. Often enough I want to assign new values to the elements in the list. I have no need for the old value, that is also provided by enumerate. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
[EMAIL PROTECTED] wrote: Terry Hancock wrote: snip So I like Python's slicing because it bites *less* than intervals in C or Fortran. I disagree. Programming languages should not needlessly surprise people, and a newbie to Python probably expects that x[1:3] = [x[1],x[2],x[3]] . Array-oriented languages, such as Fortran 90/95, Matlab/Octave/Scilab, and S-Plus/R do not follow the Python convention, and I don't know of Fortran or R programmers who complain (don't follow Matlab enough to say). There are Python programmers, such as the OP and me, who don't like the Python convention. What languages besides Python use the Python slicing convention? The principle of least surprise is all very well, but needless surprise of newbies is a dangerous criterion to adopt for programming language design and following it consistently would lead to a mess like Visual Basic, which grew by accretion until Microsoft realized it was no longer tenable and broke backward compatibility. Along the same lines, I think the REQUIREMENT that x[0] rather than x[1] be the first element of list x is a mistake. At least the programmer should have a choice, as in Fortran or VBA. In C starting at 0 may be justified because of the connection between array subscripting and pointer arithmetic, but Python is a higher-level language where such considerations are less relevant. But Pythonicity required that there should be one obvious way to do something. How obvious is having two ways? Then when you read code you would continually be asking yourself is this a one-based or a zero-based structure?, which is not a profitable use of time. regards Steve -- Steve Holden+1 703 861 4237 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ Python Web Programming http://pydish.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Antoon Pardon wrote: I sometimes think python should have been more explicite here, using a marker for the start-index and end-index, may '^' and '$'. So if you wanted the last element you had to write: lst[$] And for the next to last element: lst[$ - 1] This would make accessing list elements counted from the rear almost just as easy as it is now but wouldn't interfere with the ask forgiveness programming style. How would you pass this argument to __getitem__? What would be allowed, only '$-x' or also '$+x' or what else? What type would '$' be? Reinhold -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
Maxim Kasimov wrote: 1) goto exempts from necessity to install new software (it is critical for remote working, for example, installing X11 may be impossible at all) Attributing the need for a language feature to restrictions of your ambience is hilarious. Reinhold -- http://mail.python.org/mailman/listinfo/python-list
Re: Dictionary question.
On 21 Apr 2005 02:47:42 -0700, hawkesed [EMAIL PROTECTED] wrote: I am semi new to Python. Here is my problem : I have a list of 100 random integers. I want to be able to construct a histogram out of the data. So I want to know how many 70's, 71's, etc. I can't figure out how to do this. A dictionary is supposedly can do key value pairs right? I want to be able to see if say 75 is in the data structure, and what its value is, then increment its value as I go through the list finding items. I am sure there is a way to do this. Is a dictionary what I should be using? Thanks for any help. Hope this makes sense, its getting very late here. Sounds like homework, so I'll just say that yes, a dictionary would be ideal for what you are trying to do. -- Cheers, Simon B, [EMAIL PROTECTED], http://www.brunningonline.net/simon/blog/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Dictionary question.
Simon Brunning wrote: On 21 Apr 2005 02:47:42 -0700, hawkesed [EMAIL PROTECTED] wrote: I am semi new to Python. Here is my problem : I have a list of 100 random integers. I want to be able to construct a histogram out of the data. So I want to know how many 70's, 71's, etc. I can't figure out how to do this. A dictionary is supposedly can do key value pairs right? I want to be able to see if say 75 is in the data structure, and what its value is, then increment its value as I go through the list finding items. I am sure there is a way to do this. Is a dictionary what I should be using? Thanks for any help. Hope this makes sense, its getting very late here. Sounds like homework, so I'll just say that yes, a dictionary would be ideal for what you are trying to do. And I will add that you have two different cases to cope with: the first time you come across a particular value you have to create a new element with a value of one. The second and subsequent times you have to add one to an existing element. regards Steve -- Steve Holden+1 703 861 4237 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ Python Web Programming http://pydish.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Op 2005-04-21, Reinhold Birkenfeld schreef [EMAIL PROTECTED]: Antoon Pardon wrote: I sometimes think python should have been more explicite here, using a marker for the start-index and end-index, may '^' and '$'. So if you wanted the last element you had to write: lst[$] And for the next to last element: lst[$ - 1] This would make accessing list elements counted from the rear almost just as easy as it is now but wouldn't interfere with the ask forgiveness programming style. How would you pass this argument to __getitem__? Well assuming lst.last, was the last index of lst, __getitem__ would get lst.last and lst.last - 1 passed. What would be allowed, only '$-x' or also '$+x' or what else? Any expression where an int is allowed. What type would '$' be? It would be an int. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Op 2005-04-21, Steve Holden schreef [EMAIL PROTECTED]: [EMAIL PROTECTED] wrote: Terry Hancock wrote: snip So I like Python's slicing because it bites *less* than intervals in C or Fortran. I disagree. Programming languages should not needlessly surprise people, and a newbie to Python probably expects that x[1:3] = [x[1],x[2],x[3]] . Array-oriented languages, such as Fortran 90/95, Matlab/Octave/Scilab, and S-Plus/R do not follow the Python convention, and I don't know of Fortran or R programmers who complain (don't follow Matlab enough to say). There are Python programmers, such as the OP and me, who don't like the Python convention. What languages besides Python use the Python slicing convention? The principle of least surprise is all very well, but needless surprise of newbies is a dangerous criterion to adopt for programming language design and following it consistently would lead to a mess like Visual Basic, which grew by accretion until Microsoft realized it was no longer tenable and broke backward compatibility. Along the same lines, I think the REQUIREMENT that x[0] rather than x[1] be the first element of list x is a mistake. At least the programmer should have a choice, as in Fortran or VBA. In C starting at 0 may be justified because of the connection between array subscripting and pointer arithmetic, but Python is a higher-level language where such considerations are less relevant. But Pythonicity required that there should be one obvious way to do something. How obvious is having two ways? How obvious is that lists can be any length? Do you consider it an unbounded number of ways, that lists can be any length? Like users have a choice in how long they make a list, they should have a choice where the indexes start. (And that shouldn't be limited to 0 and 1). Then when you read code you would continually be asking yourself is this a one-based or a zero-based structure?, which is not a profitable use of time. No you wouldn't. If you have the choice you just take the start index that is more natural. Sometimes that is 0 sometimes that is 1 and other times it is some whole other number. The times I had the opportunity to use such structures, the question of whether it was zero-based or one-based, rarely popped up. Either it was irrelevant or it was clear from what you were processing. That you are forced to use zero-based structures, while the problem space you are working on uses one-based structures is a far bigger stumbling block where you continually have to be aware that the indexes in your program are one off from the indexes the problem is expressed in. The one obvious way is to use the same index scheme as the one that is used in the specification or problem setting. Not to use always zero no matter what. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Antoon Pardon wrote: Op 2005-04-21, Reinhold Birkenfeld schreef [EMAIL PROTECTED]: Antoon Pardon wrote: I sometimes think python should have been more explicite here, using a marker for the start-index and end-index, may '^' and '$'. So if you wanted the last element you had to write: lst[$] And for the next to last element: lst[$ - 1] This would make accessing list elements counted from the rear almost just as easy as it is now but wouldn't interfere with the ask forgiveness programming style. How would you pass this argument to __getitem__? Well assuming lst.last, was the last index of lst, __getitem__ would get lst.last and lst.last - 1 passed. Then it would be an alias for len(lst)-1 ? What would be allowed, only '$-x' or also '$+x' or what else? Any expression where an int is allowed. Okay. What type would '$' be? It would be an int. Where would it be allowed? Only in subscriptions? Reinhold -- http://mail.python.org/mailman/listinfo/python-list
Re: python LEX
Hello jozo, I have to work on python lexical definition in Lex. I spent lots of my time to find regular expresions written for Lex of Python language but nothing. Can somebody help me? http://www.antlr.org/grammar/list (search for Python) You can search in projects like Pyrex and Parrot for their parser implementation. HTH. -- Miki Tebeka [EMAIL PROTECTED] http://tebeka.bizhat.com The only difference between children and adults is the price of the toys pgpQmhuX2LvAQ.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: memory profiler?
Peter Hansen wrote: John Reese wrote: Is there a memory or heap profiler for python programs? So that, for example, if a program was bloating over time I could see how many of each object there were and maybe even where the references were? The gc module has a variety of helpful features like that. I created a qt-based memory analyzer on top of the gc module. I plan to release it soon - it has been helpful to me for a few projects. Its a client-server application that collects data through an in-process running thread that delivers object histograms. The client fetches these and allows to display the development of objects based various criteria over the time. It can also record these data for offline-analysis. So far the in-proccess threads communicate their histograms either by pyro or xmlrpc servers. Unfortunately debugging ZOPE with the xmlrpc server lead to a mem-leak itself :( - so currently I'm no confident enough to release it. -- Regards, Diez B. Roggisch -- http://mail.python.org/mailman/listinfo/python-list
Re: deprecation of has_key?
Luis Bruno wrote:
Hello,
Steve Holden wrote:
Two words: backward compatibility. To lose that method now would break
thousands of existing programs. The 2.4 library would probably
experience breakage too ... let's see:
$ find /lib/python2.4/ -name *.py -exec grep has_key {} \; | wc -l
587
Is there any interest in changing that to the key in dict sintax?
The general principles on which maintenance is based for Python decree
that such changes not be made gratuitously: the code as it is works now,
so it is only worth changing when has_key is removed.
If a module were being edited for other reasons there would be no
objection to removal of the has_key usage then, but the chance of
breakage due to careless modification is high enough to want to avoid it
unless really *necessary*.
regards
Steve
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Re: Why Python does *SLICING* the way it does??
Op 2005-04-21, Reinhold Birkenfeld schreef [EMAIL PROTECTED]: Antoon Pardon wrote: Op 2005-04-21, Reinhold Birkenfeld schreef [EMAIL PROTECTED]: Antoon Pardon wrote: I sometimes think python should have been more explicite here, using a marker for the start-index and end-index, may '^' and '$'. So if you wanted the last element you had to write: lst[$] And for the next to last element: lst[$ - 1] This would make accessing list elements counted from the rear almost just as easy as it is now but wouldn't interfere with the ask forgiveness programming style. How would you pass this argument to __getitem__? Well assuming lst.last, was the last index of lst, __getitem__ would get lst.last and lst.last - 1 passed. Then it would be an alias for len(lst)-1 ? In the context of current python lists yes. But if you would go further and allow lists to start from an other index than 0 then not. What would be allowed, only '$-x' or also '$+x' or what else? Any expression where an int is allowed. Okay. What type would '$' be? It would be an int. Where would it be allowed? Only in subscriptions? Yes, the idea would be that the brackets indicate a scope where $ would be the last index and ^ would be the first index. So if you wanted the middle element you could do: lst[(^ + $) // 2] But outsides the brackets the scope where this has any meaning wouldn't be present. Not that I think this idea has any chance. Already I can hear people shout that this is too perlish. But here is another idea. Sometime ago I read about the possibility of python acquiring a with statement. So that instead of having to write: obj.inst1 ... obj.inst2 ... obj.inst1 ... You could write: with obj: .inst1 ... .inst2 ... .inst1 ... If this would get implemented we could think of a left bracked as implicitely exucting a with statement. If we then had a list like class where the start-index could be different from zero and which had properties first and last indicating the first and last index we could then write something like: lst[.last] for the last element or lst[.last - 1] for the next to last element. lst[.first] for the first element lst[(.first + .last) // 2] for the middle element Maybe this makes the proposal again pythonic enough to get a little consideration. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
Maxim Kasimov [EMAIL PROTECTED] writes: 1. comment for debug It can be used in the same way, as the comments for debugging are used, but it will be easier than to use or ''', or using features of text-editors, when it is necessary to comment piece of code which already contains ''' or/and strings already, or there is another #-comments. Using goto, you do not need to edit a code, which is unfamiliar to you. ... and then you end up with situation when another goto jumps directly into the body of the code you've just commented with your goto. Happy debugging! BTW, don't you want comefrom statement to be added to the language to make debugging even more fun? -- Sergei. -- http://mail.python.org/mailman/listinfo/python-list
Python Mayavi Problem
Hi,
I read your Mayavi question from about a year ago, because I
have exactly the same problem. I believe it has to do with windows, because I have
seen it work under Linux. Did anyone reply to your query and if so, do you know
why the screen goes red?
I attached your email so that you know what I am talking
about.
Thanks
Alexej
Hello NG, I'm trying to follow the mayavi documentation in order to runmayavi from python. In Chapter 4. Using MayaVi from Python, there isa simple example like this:# generate the data.from Numeric import *import scipyx = (arange(50.0)-25)/2.0y = (arange(50.0)-25)/2.0r = sqrt(x[:,NewAxis]**2+y**2)z = 5.0*scipy.special.j0(r) # Bessel function of order 0# now dump the data to a VTK file.import pyvtk# Flatten the 2D array data as per VTK's requirements.z1 = reshape(transpose(z), (-1,))point_data = pyvtk.PointData(pyvtk.Scalars(z1))grid = pyvtk.StructuredPoints((50,50, 1), (-12.5, -12.5, 0), (0.5,0.5, 1))data = "" point_data)data.tofile('test.vtk')import mayaviv = mayavi.mayavi() # create a MayaVi window.d = v.open_vtk('test.vtk', config=0) # open the data file.# The config option turns on/off showing a GUI control for thedata/filter/module.# load the filters.f = v.load_filter('WarpScalar', config=0) n = v.load_filter('PolyDataNormals', 0)n.fil.SetFeatureAngle (45) # configure the normals.# Load the necessary modules.m = v.load_module('SurfaceMap', 0)a = v.load_module('Axes', 0)a.axes.SetCornerOffset(0.0) # configure the axes module.o = v.load_module('Outline', 0)v.Render() # Re-render the scene.Everything goes fine, but at the end I obtain the mayavi windowcompletely red (without the expected surface/image), and when I clickon this window I get different errors depending on which Python editorI run:1) Pythonwin: Error: Microsoft Visual C++ Runtime Error. EverythingCrashes. After this, I get a vtkwindow coming up and showing me thealways-present error message from mayavi:Generic Warning: In /debian/stage/vtk-4.2.4/Rendering/vtkTkRenderWidget.cxx, line 638A TkRenderWidget is being destroyed before it associatedvtkRenderWindowis destroyed. This is very bad and usually due to the order in which objects are being destroyed. Always destroy the vtkRenderWindow beforedestroying the user interface componentsI don't know why, but with mayavi this warning is EXTREMELY common...2) IDLE for Python: All is frozen, nothing happen, I have to killPython;3) Python Command Line: No windows appears, nothing happen.Moreover, I would like to be able to compile my Python application toa standalone EXE file by using py2exe, but py2exe complains about somemissing modules (either from mayavi and for scipy), and the createdEXE does not start.I have installed Python using the Enthought Installer for Python (withlots of site-packages inside), located at:http://www.enthought.com/python/I'm running Win2000, without administrator privileges (if this canmake differences).Does anyone have an idea?Thanks for every suggestion.Andrea.
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Re: goto statement
Tim Daneliuk [EMAIL PROTECTED] writes: [...] Some HLLs almost have to have it by definition. I cut my teeth as programmer writing for embedded realtime systems in a HLL (PL/M). While you could, in theory, completely avoid 'goto' in a realtime environment, it would make all manner of practical programming problems kind of ugly to implement. BTW, all modern systems come complete with 'goto' implemented in *hardware* - they're called interrupts. Well, I'm writing for embedded realtime systems in C/C++ and have never encountered a single need to use goto. Comparing interrupts to goto doesn't make any sense for me either. For example, most architectures have 'branch' *hardware* instructions that are much more close equivalents to goto than interrupts are, but that doesn't justify use of goto in high-level languages in any way. -- Sergei. -- http://mail.python.org/mailman/listinfo/python-list
Re: Lex
jozo wrote: I NEED HELP!!! Shouting won't give you help. Reading this http://www.catb.org/~esr/faqs/smart-questions.html and coming back with a more elaborate question might. -- Regards, Diez B. Roggisch -- http://mail.python.org/mailman/listinfo/python-list
Re: Define Constants
Thanks for the input. i am renaming my module to be customthing. I noticed that is how many python modules are, so I will stick to the convention. Thanks for the help. -- http://mail.python.org/mailman/listinfo/python-list
Design advice for unit test asserters
I'm working on a project where I'm doing various file manipulations. I'm not familiar with the idioms are common or good for this situation, so I'd appreciate advice and suggestions. Question 1: A number of checks apply to a set of files. So I'm wondering whether to have something like: def test_SomeTest(...): ... self.AssertAllFilesExist(fileList) or def test_SomeTest(...): ... [ self.AssertFileExists(f) for f in fileList ] In a statically typed, tiny method design approach, the former would be preferred. But in Python the latter seems easy enough and more natural. And I'm wondering if I'm missing some other Python idiom that would be even better. Question 2: A more complicated example: My object defines its own conditions that can be queried, e.g. def test_SomeTest(...): myObject.DoSomething() self._assert(myObject.isFileTypeQ(someFile)) but the parameter someFile is often an expression that should be encapsulated into the assertion. This gives me two possibilities: I can define a stand-alone query that takes myObject as a parameter: def AssertIsTypeQ(theObjectBeingTested, rawFileInfo): someComputedFile = DoStuff(rawFileInfo) return theObjectBeingTested.isFileTypeQ(someComputedFile) and then call it from within various tests as: self._assert(AssertIsFileTypeQ(myObject, someFile) or I can define an intermediate unit test case: class myTester(unittest.TestCase): def AssertIsFileTypeQ(self, rawFileInfo): someComputedFile = DoStuff(rawFileInfo) self.theObject.isFileTypeQ(someComputedFile) and then define my test cases as class test_MyObjectX(myTester): def test_Sometest(): self.theObject = ClassBeingTested() self.theObject.DoSomething() self.AssertIsFileTypeQ(someFile) With these simple cases, this seems like six of one and a half dozen of the other. But the problem grows, in that there are several of these assertions, and they often need to be applied to lists of things. At one point I was getting really complicated by abstracting out both the looping and the computed file names, passing in a functor containing the simple test and the name (for the message). I gave up on this and now I'm leaning towards the first, but again, I wonder if I'm missing a better or more natural way to solve this problem. Thanks, Gary -- http://mail.python.org/mailman/listinfo/python-list
Re: Python instances
Bengt Richter wrote:
The following shows nothing static anywhere, yet a class has been defined, an
instance created, and
__init__ called with initial value, and the value retrieved as an attribute of
the returned instance,
and it's all an expression.
type('C', (), {'__init__': lambda
self,v:setattr(self,'foo',v)})('hello').foo
'hello'
I have no idea what point you are trying to make, except maybe that it is possible to obfuscate a
simple class definition.
Kenw
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Re: goto statement
implement. BTW, all modern systems come complete with 'goto' implemented in *hardware* - they're called interrupts. That's not goto - that is a asynchronous function call - much closer related to multithreading. In an interrupt, you can always jump back to the main program using rte (return from interrupt) - or whatever that is called on the respective processor. Of course you _can_ alter all sorts of state, including the stackframe and the PC when inside an interrupt - thus you can create goto for e.g. multithreading. But I wouldn't call that builtin-goto... -- Regards, Diez B. Roggisch -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
Sergei Organov wrote: Maxim Kasimov [EMAIL PROTECTED] writes: 1. comment for debug It can be used in the same way, as the comments for debugging are used, but it will be easier than to use or ''', or using features of text-editors, when it is necessary to comment piece of code which already contains ''' or/and strings already, or there is another #-comments. Using goto, you do not need to edit a code, which is unfamiliar to you. and then you end up with situation when another goto jumps directly into the body of the code you've just commented with your goto. Happy debugging! BTW, don't you want comefrom statement to be added to the language to make debugging even more fun? if you can't control what you do - it is you private problem, not mine. Is't it? -- Best regards, Maxim Kasimov mailto: [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Using Jython in Ant Build Process
Maurice LING wrote: I am looking for a way to use Jython in Ant build process. I have some pure Python scripts (not using any C extensions) that I'll like to incorporate into Java using Jython. I heard that this can be done but you can I set up Ant to do this? Sorry, I'm no expert with Ant. The ant script task lets you embed Jython in Ant build files using Bean Scripting Framework. See the Ant docs for script for some (non-Jython) examples. The links in the Ant docs are out-of-date. BSF is here: http://jakarta.apache.org/bsf/manual.html Jython is here: http://www.jython.org Kent -- http://mail.python.org/mailman/listinfo/python-list
freeze and expat
I am playing around with jabberpy, and on a lark decided to try to freeze one of the included samples, test_client.py The freeze/build worked fine, but when I attempted to run the resulting binary, I got an error hinting that it couldn't find parsers.expat: canal:/home/chris/build% ./test_client Traceback (most recent call last): File /home/chris/build/../test_client.py, line 15, in ? import jabber File /usr/lib/python2.3/site-packages/jabber.py, line 67, in ? import xmlstream File /usr/lib/python2.3/site-packages/xmlstream.py, line 36, in ? import xml.parsers.expat ImportError: No module named parsers.expat I have tried this with python2.3.5 and 2.4.1, and played around with the -m option on the freeze cmd line, but no joy. Google seems to delight in frustating me... In a much simpler case than the test_client.py, the following also fails: import xml.parsers.expat print Hello world Though it runs from the interpreter... ideas? -- [EMAIL PROTECTED] | Roma Invicta! -- http://mail.python.org/mailman/listinfo/python-list
Re: (Python newbie) Using XP-SP2/MSVC6: No Python24_d.lib, winzip barfs on Python-2.4.1.tar, cannot download bzip2
If you're really desperate, write a python script that changes - #include python.h to #ifdef _DEBUG #undef _DEBUG #include python.h #define _DEBUG #else #include python.h #endif Then run the script each time you generate a new wrapper file and everything ought to be OK. jw On 4/20/05, Bill Davy [EMAIL PROTECTED] wrote: Hi Jaime, SWIG-1.3.24/Lib/python/python.swg does not have the [#include python.h] but has lots of Pythonesque includes but all *.swg Still, I am hoping I can make MSVC6 do some of the work of putting things in the right place for Release and Debug builds. Rgds, Bill. Jaime Wyant [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED]... I fight the python24_d.lib problem with swig daily. The way I got around it was to modify swig's python configuration module. Mine was located at /lib/swig1.3/python/python.swg (I'm using cygwin) At the top, I changed #include python.h to #ifdef _DEBUG #undef _DEBUG #include python.h #define _DEBUG #else #include python.h #endif Somewhere in the includes, python uses a pragma telling the MSVC compiler which library to link the object files against. Because you're building a _DEBUG build, you magically get the python24_d.lib library. hth, jw On 4/18/05, Bill Davy [EMAIL PROTECTED] wrote: I downlaoded and installed http://www.python.org/ftp/python/2.4.1/python-2.4.1.msi I'm trying to build an extension using SWIG 1.3.24 and the linker needs python24_d.lib (I do not have the DLL either). I've not found it in any of the downloads. So I tried to download the source to build it myself. Of http://www.python.org/ftp/python/2.4.1/Python-2.4.1.tar.bz2 and http://www.python.org/ftp/python/2.4.1/Python-2.4.1.tgz, WinZip (9.0 SR1) just says Error reading header after processing 0 entries. Additionally, I've had no joy downloading the unzipper (ftp://sources.redhat.com/pub/bzip2/v102/bzip2-102-x86-win32.exe) from the site cited for the unzipper (http://sources.redhat.com/bzip2/). It flashed up a black console window momentarily. Oh, this is so frustrating! :-( Can anyone point me in the right direction? And then I can get to grips with my work. tia Bill -- http://mail.python.org/mailman/listinfo/python-list -- -- http://mail.python.org/mailman/listinfo/python-list
Re: Design advice for unit test asserters
Gary wrote: I'm working on a project where I'm doing various file manipulations. I'm not familiar with the idioms are common or good for this situation, so I'd appreciate advice and suggestions. Question 1: A number of checks apply to a set of files. So I'm wondering whether to have something like: def test_SomeTest(...): ... self.AssertAllFilesExist(fileList) or def test_SomeTest(...): ... [ self.AssertFileExists(f) for f in fileList ] Personally I avoid using list comprehensions with side-effects; if I don't actually want the list I write it out: for f in fileList: self.AssertFileExists(f) Question 2: A more complicated example: My object defines its own conditions that can be queried, e.g. def test_SomeTest(...): myObject.DoSomething() self._assert(myObject.isFileTypeQ(someFile)) but the parameter someFile is often an expression that should be encapsulated into the assertion. This gives me two possibilities: I can define a stand-alone query that takes myObject as a parameter: def AssertIsTypeQ(theObjectBeingTested, rawFileInfo): someComputedFile = DoStuff(rawFileInfo) return theObjectBeingTested.isFileTypeQ(someComputedFile) I would write this method to actually do the assertion: def AssertIsTypeQ(theObjectBeingTested, rawFileInfo): someComputedFile = DoStuff(rawFileInfo) self.assert_(theObjectBeingTested.isFileTypeQ(someComputedFile)) and then call it from within various tests as: self.AssertIsFileTypeQ(myObject, someFile) I think of it as extending the standard assertions with domain-specific ones. I often write methods called checkSomething() that do a bit of work and check the result. So I might actually call the above method something like checkDoStuffIsFileTypeQ(). So, the convention I use is - write assertSomething() primitives that just check a condition - write checkSomething() methods that do some work and check the result - build the actual tests using the above Kent -- http://mail.python.org/mailman/listinfo/python-list
Re: XML parsing per record
I'll first try it using SAX, because I want to have as little dependancies
as possible. I already have BioPython as a dependancy. And I personally
don't like to install lot's of packages for a program to work. So I don't
want to impose that on other people.
But thanks anyway and I might go for the cElementTree later on, if the
ordinary SAX proves to slow...
On Wed, 20 Apr 2005 08:03:00 -0400,
Kent Johnson wrote:
Willem Ligtenberg wrote:
Willem Ligtenberg [EMAIL PROTECTED] wrote:
I want to parse a very large (2.4 gig) XML file (bioinformatics
ofcourse :)) But I have no clue how to do that. Most things I see read
the entire xml file at once. That isn't going to work here ofcourse.
So I would like to parse a XML file one record at a time and then be
able to store the information in another object. How should I do
that?
The XML file I need to parse contains information about genes.
So the first element is a gene and then there are a lot sub-elements with
sub-elements. I only need some of the informtion and want to store it in
my an object called gene. Lateron this information will be printed into a
file, which in it's turn will be fed into some other program.
This is an example of the XML
?xml version=1.0?
!DOCTYPE Entrezgene-Set PUBLIC -//NCBI//NCBI Entrezgene/EN
NCBI_Entrezgene.dtd
Entrezgene-Set
Entrezgene
snip
/Entrezgene
/Entrezgene-Set
This should get you started with cElementTree:
import cElementTree as ElementTree
source = 'Entrezgene.xml'
for event, elem in ElementTree.iterparse(source):
if elem.tag == 'Entrezgene':
# Process the Entrezgene element
geneid =
elem.findtext('Entrezgene_track-info/Gene-track/Gene-track_geneid')
print 'Gene id', geneid
# Throw away the element, we're done with it
elem.clear()
Kent
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Re: Define Constants
A recipe for Constants in Python by Alex Martelli is at http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/65207 . -- http://mail.python.org/mailman/listinfo/python-list
recording data between [ and ]
Output from 'netstat -b' on a win2003 server will show what binary is responsible for the connection. For example, it may list something like this along with other connection specific data: [lsass.exe] [System] [firefox.exe] [iexplorer.exe] How might I process the output so that anything within brackets is recorded to a log file of my own making? I know how to parse and record things to a file, I don't know how to look make '[' and ']' appear as special characters so that I can record what's between them. Basically, I want a script that will read output and stop each time it encounters a '[' and record until it gets to ']' where upon it would stop recording and then proceed on repeating the above operation as it goes thru the remaining data. Thanks, rbt -- http://mail.python.org/mailman/listinfo/python-list
Private class?
Hi,
First, I come from a Java background.
Ok, so I have this idea that I want to create an EventBus...basically
a central class where objects can register themselves as listeners for
different events. This central class also has methods so that objects
can fire events. Something like this...
Say we have object MrTree and object MotherNature. MrTree listens for
EVENT_GROW_LEAVES. So, when MrTree hears about EVENT_GROW_LEAVES,
MrTree will do just that, grow some leaves. So, while our python app
is running, MotherNature needs to tell MrTree to grow leaves. I am
suggesting something like this...
1. MrTree has a method, growLeaves()
2. MrTree registers for the event, EventBus.register(MrTree,
EVENT_GROW_LEAVES)
3. MotherNature fires grow leaves, EventBus.fire(EVENT_GROW_LEAVES)
4. MrTree's growLeaves method gets called by EventBus.
Now, in Java I would make EventBus a Singleton so that only one
instance of it would exist. And I would have MrTree implement
EventListener interface, where the interface defines a method like
growLeaves(). So when MotherNature tells the EventBus to fire the
event, EventBus loops through it's list of listeners and calls,
growLeaves()
How would I go about doing this in Python? Here is my quick idea
class EventListener:
def eventOccurred(self, eventType): pass
class MrTree(EventListener):
def __init__(self):
EventListener.__init__(self)
EventBus.register(self, EventBus.EVENT_GROW_LEAVES)
def eventOccurred(self, eventType):
if eventType == EventBus.EVENT_GROW_LEAVES:
print Growing Leaves
class EventBus:
EVENT_GROW_LEAVES = 0
__listeners = {}
def register(listener, eventType):
if __listeners.has_key(eventType):
curListeners = __listeners.get(eventType)
curListeners.append(listener)
else:
__listeners[eventType] = [listener]
def fire(eventType):
if __listeners.has_key(eventType):
x = __listeners.get(eventType)
for l in x:
l.eventOccurred(eventType)
class MotherNature:
def doSomeStuff():
print doing whatever Mother Nature does...
EventBus.fire(EventBus.EVENT_GROW_LEAVES)
...so that is what I am thinking. However, i guess my issue is how to
make EventBus a singleton or prevent it from being instaniated and
making it's methods statically accessible.
thanks.
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Re: XML parsing per record
Sorry I just decided that I want to use your solution, but I am wondering
is cElemenTree in expat or is that something different?
On Wed, 20 Apr 2005
08:03:00 -0400, Kent Johnson wrote:
Willem Ligtenberg wrote:
Willem Ligtenberg [EMAIL PROTECTED] wrote:
I want to parse a very large (2.4 gig) XML file (bioinformatics
ofcourse :)) But I have no clue how to do that. Most things I see read
the entire xml file at once. That isn't going to work here ofcourse.
So I would like to parse a XML file one record at a time and then be
able to store the information in another object. How should I do
that?
The XML file I need to parse contains information about genes.
So the first element is a gene and then there are a lot sub-elements with
sub-elements. I only need some of the informtion and want to store it in
my an object called gene. Lateron this information will be printed into a
file, which in it's turn will be fed into some other program.
This is an example of the XML
?xml version=1.0?
!DOCTYPE Entrezgene-Set PUBLIC -//NCBI//NCBI Entrezgene/EN
NCBI_Entrezgene.dtd
Entrezgene-Set
Entrezgene
snip
/Entrezgene
/Entrezgene-Set
This should get you started with cElementTree:
import cElementTree as ElementTree
source = 'Entrezgene.xml'
for event, elem in ElementTree.iterparse(source):
if elem.tag == 'Entrezgene':
# Process the Entrezgene element
geneid =
elem.findtext('Entrezgene_track-info/Gene-track/Gene-track_geneid')
print 'Gene id', geneid
# Throw away the element, we're done with it
elem.clear()
Kent
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Strings
I've having trouble coming to grip with Python strings. I need to send binary data over a socket. I'm taking the data from a database. When I extract it, non-printable characters come out as a backslash followed by a three numeric characters representing the numeric value of the data. I guess this is what you would call a raw Python string. I want to convert those four characters ( in C-think, say \\012 ) into a single character and put it in a new string. There's probably a simple way to do it, but I haven't figured it out. What I've done so far is to step through the string, character by character. Normal characters are appended onto a new string. If I come across a '\' character, I look for the next three numeric characters. But I don't know how to convert this code into a single character and append it onto the new string. I'm sure what I'm doing is long and convoluted. Any suggestions would be appreciated. Dan -- http://mail.python.org/mailman/listinfo/python-list
Re: Private class?
On Apr 21, 2005, at 15:13, codecraig wrote: ...so that is what I am thinking. However, i guess my issue is how to make EventBus a singleton or prevent it from being instaniated and making it's methods statically accessible. Not directly related to your question, but... you may want to take a look at NSNotification Co. for, er, inspiration :) Introduction to Notifications http://developer.apple.com/documentation/Cocoa/Conceptual/ Notifications/index.html Here is a -gasp- Java implementation as well: http://dev.alt.textdrive.com/file/ZOE/Frameworks/SZFoundation/ SZNotification.java Cheers -- PA, Onnay Equitursay http://alt.textdrive.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: XML parsing per record
On 4/21/05, Willem Ligtenberg [EMAIL PROTECTED] wrote: Sorry I just decided that I want to use your solution, but I am wondering is cElemenTree in expat or is that something different? Nope, cElemenTree is very much its own man. See http://effbot.org/zone/celementtree.htm. -- Cheers, Simon B, [EMAIL PROTECTED], http://www.brunningonline.net/simon/blog/ -- http://mail.python.org/mailman/listinfo/python-list
Re: XML parsing per record
Don't assume that just because you have a 2.4G XML file that you have 2.4G of data. Looking at these verbose tags, plus the fact that the XML is pretty-printed (all those leading spaces - not even tabs! - add up), I'm guessing you only have about 5-10% actual data, and the rest is just XML tagging/untagging and spaces. (For example, 373 characters used to represent a date/time - this is a sin!) As XML goes, this looks pretty dead easy to parse with non-XML parser means. It looks like all of your leaf nodes open and close on the same line, which would be easy to extract with regexp's or pyparsing. Especially since you mention I only need some of the informtion, you don't even have to build a full document tree representation. SAX parsers would also be good, since you could only trigger on the matching subset of tags that you are really interested in. Lastly, you could even try a pyparsing approach. I usually don't recommend pyparsing for XML since there are already many good XML-targeted tools out there, but it is very easy to throw together something in pyparsing that extracts, say, all of the object-id_id entries, or all of the gene-source structures. What is the subset of information you are looking to extract? -- Paul -- http://mail.python.org/mailman/listinfo/python-list
__del__ and reference count problem
Hi, i'm starting work and a simple database layer and wanted to use the __del__ to open and close a connection. However, i get an erro when executing this script: class Table: refcount = 0 def __init__(self, name): self.name = name print table %s % repr(self) Table.refcount += 1 print refcount = %s % str(Table.refcount) def __del__(self): Table.refcount -= 1 if (Table.refcount == 0): print Last table standing else: print There is/are still %d table(s) left. % Table.refcount def __getitem__(self,item): return not implemented def howMany(self): if (Table.refcount == 1): print Only 1 table else: print There are %d tables active. % Table.refcount if __name__ == '__main__': suppliera = Table(suppliers) supplierb = Table(suppliers) print Supplier returned from a %s: %s % (1, suppliera[1]) print Supplier returned from b %s: %s % (2, supplierb[2]) suppliera.howMany() supplierb.howMany() This produces the following output and error: table __main__.Table instance at 0x008D5C10 refcount = 1 table __main__.Table instance at 0x008D5C38 refcount = 2 Supplier returned from a 1: not implemented Supplier returned from b 2: not implemented There are 2 tables active. There are 2 tables active. Exception exceptions.AttributeError: 'NoneType' object has no attribute 'refcount' in bound method Table.__del__ of __main__.Table instance at 0x008D5C10 ignored Exception exceptions.AttributeError: 'NoneType' object has no attribute 'refcount' in bound method Table.__del__ of __main__.Table instance at 0x008D5C38 ignored What am i doing wrong? Thanks Benedict -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
On 2005-04-21, Sergei Organov [EMAIL PROTECTED] wrote: Well, I'm writing for embedded realtime systems in C/C++ and have never encountered a single need to use goto. I have encountered situations in C programs where the best thing to use was a goto. Those situations have always been handled beutifully by a raise in Python. Comparing interrupts to goto doesn't make any sense for me either. For example, most architectures have 'branch' *hardware* instructions that are much more close equivalents to goto than interrupts are, but that doesn't justify use of goto in high-level languages in any way. I agree. The jump or branch instruction corresponds exactly to a goto. An interrupt is more like a signal and a signal handler in C. Sort of like an asynchronous function call or thread context switch. -- Grant Edwards grante Yow! Now that we're at in LOVE, you can BUY visi.comthis GOLDFISH for a 48% DISCOUNT. -- http://mail.python.org/mailman/listinfo/python-list
python classes/file structure
What is the best/common way to structure ur python code for an application? For example...if I create some custom GUI widgets I have this C:\stuff -- gui --: MyCustomWidget.py --: TestWidgets.py so MyCustomWidget.py has one class, class MyCustomWidget: ... so from TestWidgets.py i have to do this from gui import * widget = gui.MyCustomWidget.MyCustomWidge() ...seems weird, how should I structure this? Is it not common to have one class in a .py? thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Strings
I'd use the int and chr casts. e.g.,
new_string =
a = '012'
new_string += chr(int(a))
Just in case the 012 is an octal code I'll mention that to cast to int
in general you can pass the base, as in int('034',8) or int('AF',16)
Cheers,
Keir.
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Regular Expressions - Python vs Perl
Hi, I am interested in regular expressions and how Perl and Python compare. Particulary, I am interested in performance (i.e. speed), memory usage, flexibility, completeness (i.e. supports simple and complex regex operations...basically is RegEx a strong module/library in Python?) Anyone have any information on this? Any numbers, benchmarks? Thanks so much. I know this is a python user group...but try to be has un-biased as you can. -- http://mail.python.org/mailman/listinfo/python-list
Re: recording data between [ and ]
rbt wrote: Output from 'netstat -b' on a win2003 server will show what binary is responsible for the connection. For example, it may list something like this along with other connection specific data: [lsass.exe] [System] [firefox.exe] [iexplorer.exe] How might I process the output so that anything within brackets is recorded to a log file of my own making? I know how to parse and record things to a file, I don't know how to look make '[' and ']' appear as special characters so that I can record what's between them. Does this help? import re s = '''stuff [lsass.exe] ... [System] more stuff ... x [firefox.exe] .. ... ''' re.findall(r'\[([^]]*)\]', s) ['lsass.exe', 'System', 'firefox.exe'] -Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
Do Re Mi chel La Si Do wrote: +1 I am modded up :-D -- John MexIT: http://johnbokma.com/mexit/ personal page: http://johnbokma.com/ Experienced programmer available: http://castleamber.com/ Happy Customers: http://castleamber.com/testimonials.html -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
Reinhold Birkenfeld wrote: John Bokma wrote: Mage wrote: praba kar wrote: Dear All, In Python what is equivalent to goto statement You shouldn't use goto in high-level languages. Nonsense Thank you! Above all your claim is well justified. You are probably smart enough to think of several situations that justify the use of a goto (or something that is a goto in disguise, like an early return in a function, a break or a continue, or a switch). One can abuse a goto in any language, like every other language construction. But don't make it a shouldn't like a law. Some people take Dijkstra too serious. Learn to think for yourself, I am sure he did. -- John MexIT: http://johnbokma.com/mexit/ personal page: http://johnbokma.com/ Experienced programmer available: http://castleamber.com/ Happy Customers: http://castleamber.com/testimonials.html -- http://mail.python.org/mailman/listinfo/python-list
Re: Strings
Dan wrote:
I've having trouble coming to grip with Python strings.
I need to send binary data over a socket. I'm taking the data from a
database. When I extract it, non-printable characters come out as a
backslash followed by a three numeric characters representing the
numeric value of the data. I guess this is what you would call a raw
Python string. I want to convert those four characters ( in C-think,
say \\012 ) into a single character and put it in a new string.
Does this help?
s = 'foo \\012 bar'
s.decode('string-escape')
'foo \n bar'
print s.decode('string-escape')
foo
bar
Note that the \n in the first one is because I didn't
*print* the result, but merely allowed the interpreter
to call repr() on it. repr() for a newline is of course
backslash-n, so that's what you see (inside quotation marks)
but the string itself has only 9 characters in it, as
you wished.
-Peter
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Re: goto statement
Michael Soulier wrote: On 4/20/05, Maxim Kasimov [EMAIL PROTECTED] wrote: but what if i just can't to do this becouse i'm working thrue ssh, and have to use only installed editors (such as vi) Then learn to use vi. :.,+10s/^/# comment the next 10 lines Or if you don't like that you can use sftpfs with gui editor. Mage -- http://mail.python.org/mailman/listinfo/python-list
Re: recording data between [ and ]
Peter Hansen wrote:
rbt wrote:
Output from 'netstat -b' on a win2003 server will show what binary is
responsible for the connection. For example, it may list something
like this along with other connection specific data:
[lsass.exe]
[System]
[firefox.exe]
[iexplorer.exe]
How might I process the output so that anything within brackets is
recorded to a log file of my own making? I know how to parse and
record things to a file, I don't know how to look make '[' and ']'
appear as special characters so that I can record what's between them.
Does this help?
import re
s = '''stuff [lsass.exe]
... [System] more stuff
... x [firefox.exe] ..
... '''
re.findall(r'\[([^]]*)\]', s)
['lsass.exe', 'System', 'firefox.exe']
-Peter
Yes, it does... may take me a few minutes to get my head around it
though. Why do re's have to be so arcane and complicated... especially
in Python?
It's hard to preach 'ease of use' with stuff such as this in the
language. Perhaps one day it can be rolled up into something that
*really* is easy to understand:
import string
fp = file('filename')
data = fp.read()
fp.close()
string.between(data,[,])
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Re: Private class?
codecraig said unto the world upon 2005-04-21 09:13: Hi, First, I come from a Java background. SNIP ...so that is what I am thinking. However, i guess my issue is how to make EventBus a singleton or prevent it from being instaniated and making it's methods statically accessible. thanks. I don't come from a Java, or any other language, background, so I cannot warrant that any of these will seem helpful to you. But there are a lot of Singleton and Singleton-like patterns floating about. Here's some: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66531 http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52558 http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/102187 http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/286206 http://fraca7.free.fr/blog/index.php?2005/03/23/6-design-patterns-part-iii---singleton Best, Brian vdB -- http://mail.python.org/mailman/listinfo/python-list
Re: deprecation of has_key?
On Thu, 21 Apr 2005 05:43:36 -0400 Steve Holden wrote: SH Two words: backward compatibility. To lose that method now would SH break thousands of existing programs. [...] SH The method might disappear in Python 3.0, when we will be allowed to SH break backward compatibility - you are correct in saying it's no SH longer necessary. I believe it's a bad idea to remove this method, since behavior of both item in dict and for item in dict (especially the later) in Python does't seem sane to me. Just look at reverse operations: dict.fromkeys(seq) - d.keys(), d.iterkeys() - OK dict(iterable) - d.iteritems() - why not iter(d)? dict(l) - d.items() - why not list(d)? dict(seq) - d.keys(), d.iterkeys() - looks very strange. And those (item in dict and for item in dict) are related of course, since the following should pass: for item in d: assert item in d That's the reason why I always prefer to use has_key() and iteritems() to in and iter(). Readability counts. -- Denis S. Otkidach http://www.python.ru/ [ru] -- http://mail.python.org/mailman/listinfo/python-list
Is there a package with convolution and related methods?
List: Is there a Python package with Convolution and related methods? I'm working on modeling some DSP processes in Python. I've rolled one up, but don't feel much like reinventing the wheel, especially if there's already something like Insanely Efficient FFT for Python already. Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
How can I verify that a passed argument is an interible collection?
List: I'm working on some methods that operate on (mathematical) vectors as in: def Convolution(x, y) Returns a list containing the convolution of vectors x and y Is there any way to determine at runtime that x and y are iterible collections? Do I *coughs* simply *coughs* trap the exception created by: for v in x: when v is a scaler quantity? Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: Why Python does *SLICING* the way it does??
Steve Holden wrote: The principle of least surprise is all very well, but needless surprise of newbies is a dangerous criterion to adopt for programming language design and following it consistently would lead to a mess like Visual Basic, which grew by accretion until Microsoft realized it was no longer tenable and broke backward compatibility. Well, *needless* surprise of newbies is never a good thing. If it were, it wouldn't be needless, now would it? :-) Surprising newbies just to surprise newbies is just cruel, but there is room in this world for it may suprise you now, but you'll thank us later and situations where there is a newbie way and an other way, and the other way is chosen because it's the easiest thing for the most people in the long run. But I agree, having the easiest thing for newbies as your sole criterion for language design is a road to madness, for no other reason than that newbies don't stay newbies forever. -- http://mail.python.org/mailman/listinfo/python-list
Re: deprecation of has_key?
Denis S. Otkidach wrote: I believe it's a bad idea to remove this method, since behavior of both item in dict and for item in dict (especially the later) in Python does't seem sane to me. Just look at reverse operations: dict.fromkeys(seq) - d.keys(), d.iterkeys() - OK dict(iterable) - d.iteritems() - why not iter(d)? dict(l) - d.items() - why not list(d)? dict(seq) - d.keys(), d.iterkeys() - looks very strange. And those (item in dict and for item in dict) are related of course, since the following should pass: for item in d: assert item in d That's the reason why I always prefer to use has_key() and iteritems() to in and iter(). Huh? I'm not following your logic. Why is item in dict less readable than dict.has_key(item)? Something to do with expecting inverses that don't exist? Personally, I use item in dict because it's quite readable to me, and generally faster. STeVe -- http://mail.python.org/mailman/listinfo/python-list
Re: Private class?
codecraig wrote:
class EventListener:
def eventOccurred(self, eventType): pass
The EventListener class is not needed in Python; you can include it for its documentation value if
you like but Python does not require interfaces the way Java does.
class EventBus:
EVENT_GROW_LEAVES = 0
__listeners = {}
def register(listener, eventType):
if __listeners.has_key(eventType):
curListeners = __listeners.get(eventType)
curListeners.append(listener)
else:
__listeners[eventType] = [listener]
def fire(eventType):
if __listeners.has_key(eventType):
x = __listeners.get(eventType)
for l in x:
l.eventOccurred(eventType)
...so that is what I am thinking. However, i guess my issue is how to
make EventBus a singleton or prevent it from being instaniated and
making it's methods statically accessible.
One way to do this is to make an EventBus module and make __listeners, register() and fire() be
module attributes. Your client code would look like
import EventBus
...
EventBus.register(...)
EventBus.fire(...)
Kent
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Re: goto statement
Maxim Kasimov [EMAIL PROTECTED] writes: Sergei Organov wrote: Maxim Kasimov [EMAIL PROTECTED] writes: 1. comment for debug It can be used in the same way, as the comments for debugging are used, but it will be easier than to use or ''', or using features of text-editors, when it is necessary to comment piece of code which already contains ''' or/and strings already, or there is another #-comments. Using goto, you do not need to edit a code, which is unfamiliar to you. and then you end up with situation when another goto jumps directly into the body of the code you've just commented with your goto. Happy debugging! if you can't control what you do - it is you private problem, not mine. Is't it? Hopefully I do control what I do. However, wasn't it you who spoke about code, which is unfamiliar? Obviously you advocate using goto to comment out a code that has been written by somebody else. I don't see any way for you or me to control what those somebody did with goto provided that goto is there in the language, sorry. Overall, using goto for commenting something out is not any better than or ''', as the code to be commented out could contain labels and you will need to find and comment out all the goto that jump to these labels as well. Happy debugging! -- Sergei. -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
Grant Edwards [EMAIL PROTECTED] writes: On 2005-04-21, Sergei Organov [EMAIL PROTECTED] wrote: Well, I'm writing for embedded realtime systems in C/C++ and have never encountered a single need to use goto. I have encountered situations in C programs where the best thing to use was a goto. Those situations have always been handled beutifully by a raise in Python. setjmp/longjump? -- Sergei. -- http://mail.python.org/mailman/listinfo/python-list
Re: How can I verify that a passed argument is an interible collection?
Charles Krug wrote: I'm working on some methods that operate on (mathematical) vectors as in: def Convolution(x, y) Returns a list containing the convolution of vectors x and y Is there any way to determine at runtime that x and y are iterible collections? Do I *coughs* simply *coughs* trap the exception created by: for v in x: when v is a scaler quantity? why not leave trapping exceptions to whoever uses your function? /F -- http://mail.python.org/mailman/listinfo/python-list
Re: How can I verify that a passed argument is an interible collection?
Others may know better ways but the 2 I know of are: 1) If you know that the arguments will be lists or tuples you can use isinstance(). if not isinsance(arg, (list, tuple): print arg must be list or tuple) 2) Or if you not you could see if the argument has next and __iter__ methods (more general solution) if hasattr(arg, 'next') and not hasattr(arg, '__iter__'): # perform work on iterable else: print arg must be an iterable Larry Bates Charles Krug wrote: List: I'm working on some methods that operate on (mathematical) vectors as in: def Convolution(x, y) Returns a list containing the convolution of vectors x and y Is there any way to determine at runtime that x and y are iterible collections? Do I *coughs* simply *coughs* trap the exception created by: for v in x: when v is a scaler quantity? Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: deprecation of has_key?
On Thu, 21 Apr 2005 08:50:25 -0600 Steven Bethard wrote: SB Huh? I'm not following your logic. Why is item in dict less SB readable than dict.has_key(item)? Something to do with expecting SB inverses that don't exist? SB SB Personally, I use item in dict because it's quite readable to me, SB and generally faster. For me dictionary is a collection of key-value pairs, but not a collection of keys (that's what set is). -- Denis S. Otkidach http://www.python.ru/ [ru] -- http://mail.python.org/mailman/listinfo/python-list
Re: How can I verify that a passed argument is an interible collection?
Charles Krug [EMAIL PROTECTED] wrote: Do I *coughs* simply *coughs* trap the exception created by: for v in x: when v is a scaler quantity? Sure. Why not? If you're coming from a type-bondage language like C++ or Java, it probabliy feels strange, but it's the Python way. It looks like what you want to catch is TypeError. -- http://mail.python.org/mailman/listinfo/python-list
Re: goto statement
On 2005-04-21, Sergei Organov [EMAIL PROTECTED] wrote: Grant Edwards [EMAIL PROTECTED] writes: On 2005-04-21, Sergei Organov [EMAIL PROTECTED] wrote: Well, I'm writing for embedded realtime systems in C/C++ and have never encountered a single need to use goto. I have encountered situations in C programs where the best thing to use was a goto. Those situations have always been handled beutifully by a raise in Python. setjmp/longjump? I've always found setjmp/longjmp much more confusing and hard to maintain than a simple goto. It also requires library support that goto doesn't. -- Grant Edwards grante Yow! Your CHEEKS sit like at twin NECTARINES above visi.coma MOUTH that knows no BOUNDS -- -- http://mail.python.org/mailman/listinfo/python-list
Re: recording data between [ and ]
Yes, it does... may take me a few minutes to get my head around it
though. Why do re's have to be so arcane and complicated... especially
in Python?
It's hard to preach 'ease of use' with stuff such as this in the
language. Perhaps one day it can be rolled up into something that
*really* is easy to understand:
Welcome to the wonderful world of programming. Regular expressions are what
they are because they are modeled after a certain theory - that of finite
state automata and their correspondence to certain classes of grammars. And
they require a bit of understanding. And there is no language that does
them different - some integrate them syntactically (like perl), others
don't have them available in the standard lib at all. But if you get them,
they always look like that.
import string
fp = file('filename')
data = fp.read()
fp.close()
string.between(data,[,])
how about
import whatever_is_needed
solve_my_problem()
? Seriously: Programming or maybe better saying the way we tell computers
what to do might evolve by standardization to a point where lots of tasks
get easier.You actual problem might be solved easier one day if
commandline-tools agree on a specific output format (viewed from today
thate means possibly xml) and standard tools to deal with these.
But as the world is complex and people want solutions to their complex
problems, IMHO programming will always be about such nitty gritty details.
--
Regards,
Diez B. Roggisch
--
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Re: How can I verify that a passed argument is an interible collection?
Charles Krug wrote: List: I'm working on some methods that operate on (mathematical) vectors as in: def Convolution(x, y) Returns a list containing the convolution of vectors x and y Is there any way to determine at runtime that x and y are iterible collections? Do I *coughs* simply *coughs* trap the exception created by: for v in x: when v is a scaler quantity? Yes, thats considered good practice. -- Regards, Diez B. Roggisch -- http://mail.python.org/mailman/listinfo/python-list
Re: How can I verify that a passed argument is an interible collection?
Charles Krug wrote: List: I'm working on some methods that operate on (mathematical) vectors as in: def Convolution(x, y) Returns a list containing the convolution of vectors x and y Is there any way to determine at runtime that x and y are iterible collections? Do I *coughs* simply *coughs* trap the exception created by: for v in x: when v is a scaler quantity? Sure, or if you want to do it earlier, you could try something like: def convolution(x, y): xiter = iter(x) yiter = iter(y) And then use xiter and yiter in your for loops. This will make sure that the TypeErrors get raised as soon as the function is called. STeVe -- http://mail.python.org/mailman/listinfo/python-list
Re: deprecation of has_key?
Denis S. Otkidach wrote: On Thu, 21 Apr 2005 08:50:25 -0600 Steven Bethard wrote: SB Huh? I'm not following your logic. Why is item in dict less SB readable than dict.has_key(item)? Something to do with expecting SB inverses that don't exist? SB SB Personally, I use item in dict because it's quite readable to me, SB and generally faster. For me dictionary is a collection of key-value pairs, but not a collection of keys (that's what set is). Ahh, ok. Now I understand. I think you could probably search the python-dev archives and see why the decision was made as it was. For pretty much all my purposes, key in dict is much more useful than item in dict. Practicality beats Purity and all. ;) STeVe -- http://mail.python.org/mailman/listinfo/python-list
A smallish Tkinter question
What I want: A little window to open with a 0 in it. Every second, the 0 should increment by 1. What I get: A one second delay, see the window with a 1 in it, and then nothing appears to happen. Never see the 0, never see a 2. Any quick clues? Thanks. Nick. (Python 2.4, Win98). from Tkinter import * from time import sleep class Clock: def __init__(self, parent): self.time = 0 self.display = Label(parent) self.display[font] = Arial 16 self.display[text] = str(self.time) self.display.pack() def run(self): #also tried self,parent sleep(1.0) self.time = self.time + 1 self.display[text] = str(self.time) win = Tk() app = Clock(win) app.run() #also tried run(win) with self,parent above win.mainloop() -- http://mail.python.org/mailman/listinfo/python-list
Re: Meine geilen Bilder
Hi, hier sind meine geilen Bilder! My nude Pics!!! http://www.geile-tipps.info/go/ -- Posted by News Bulk Poster Unregistered version -- http://mail.python.org/mailman/listinfo/python-list
Re: Can an object of a C type have random members added? tp_dictoffset?
On Thu, 21 Apr 2005 17:55:24 +1000 Gregory Bond wrote:
GB I have a class implemented in C using tp_members to specify (read-only)
GB access to data members in the C struct. I'd like to be able to do the
GB decoration trick with objects of this class. Is this possible?
GB
GB [The documentation for tp_dictoffset eseems to hint that this is
GB possible. how do I use it?]
Something like the following:
typedef struct {
PyObject_HEAD
PyObject *dict;
} YourObject;
static PyMemberDef module_members[] = {
{__dict__, T_OBJECT, offsetof(YourObject, dict), READONLY},
{0}
};
PyObject *
Your_New()
{
YourObject *obj;
obj = PyObject_GC_New(YourObject, Your_Type);
if (obj==NUL) return NULL;
obj-dict = PyDict_New();
if (obj-dict==NULL) {
Py_DECREF(obj);
return NULL;
}
PyObject_GC_Track(obj);
return (PyObject *)obj;
}
PyTypeObject Your_Type = {
PyObject_HEAD_INIT(PyType_Type)
# ...skipped...
offsetof(YourObject, dict), /* tp_dictoffset */
# ...skipped...
}
--
Denis S. Otkidach
http://www.python.ru/ [ru]
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