PyDev 2.3.0 Released
Hi All, PyDev 2.3.0 has been released Details on PyDev: http://pydev.org Details on its development: http://pydev.blogspot.com Release Highlights: --- * Pep8.py integrated (must be enabled in PyDev Editor Code Analysis pep8.py). * Faster PyDev startup (internal Jython upgraded to version 2.2.1 -- and also optimized for PyDev). * Action to select/deselect scope (Shift+Alt+Up/Down). * Fix: cache issue where the PYTHONPATH in memory became different from the PYTHONPATH configured for a project. * Fix: OutOfMemoryError when dealing with PyOpenGL. * Fix: deadlock (could occur in a race condition when importing a project with an existing Python configuration). * Fix: code-completion integration issue with IPython 011 (patch from jonahkichwacoders). * Fix: annotation could remain in editor after removing a marker. * Fix: BadLocationException on extract local refactoring. What is PyDev? --- PyDev is a plugin that enables users to use Eclipse for Python, Jython and IronPython development -- making Eclipse a first class Python IDE -- It comes with many goodies such as code completion, syntax highlighting, syntax analysis, refactor, debug and many others. Cheers, -- Fabio Zadrozny -- Software Developer Appcelerator http://appcelerator.com/ Aptana http://aptana.com/ PyDev - Python Development Environment for Eclipse http://pydev.org http://pydev.blogspot.com -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations/
HTSQL 2.2 : A Query Language for the Accidental Programmer
We'd like to announce the next release of HTSQL, a high-level
query language for relational databases. HTSQL is specifically
designed for data analysts web developers and makes writing and
maintaining complex queries a pleasure. HTSQL can be used as a
command-line interpreter, a WSGI application, or a Python library.
# Create an HTSQL instance.
from htsql import HTSQL
htsql = HTSQL(pgsql:htsql_demo)
# Find all schools matching the given pattern.
query = /school?name~$pattern
for row in htsql.produce(query, pattern='art'):
... print row
...
school(code=u'art', name=u'School of Art and Design', campus=u'old')
school(code=u'la', name=u'School of Arts and Humanities',
campus=u'old')
# For schools in the old campus, get # of associated programs and
departments.
query = /school{name, count(program), count(department)}?campus='old'
for row in htsql.produce(query):
... print %s: %d programs, %d departments % row
...
School of Art and Design: 3 programs, 2 departments
College of Education: 7 programs, 2 departments
School of Arts and Humanities: 9 programs, 5 departments
School of Natural Sciences: 6 programs, 4 departments
For more detailed instructions for use with Python, see
http://htsql.org/doc/embed.html
Homepage: http://htsql.org
Download: http://pypi.python.org/pypi/HTSQL
Source: http://bitbucket.org/prometheus/htsql
Since our 2.1 release, we've focused on usability improvements.
We've added a web-based query editor with syntax highlighting
completion. We also implemented a new configuration system to
provide granular meta-data customization. Finally, we added
plugins for Django and SQLAlchemy integration. For a detailed
list of changes, see http://htsql.org/blog/htsql-2.2-final.html
Please join us at #htsql on irc.freenode.net
Clark C. Evans Kirill Simonov
--
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Support the Python Software Foundation:
http://www.python.org/psf/donations/
Class: @property - .__dict__
Good morning,
I wonder if someone could please help me out with the @property
function as illustrated in the following example.
class te():
def __init__(self):
self.a = 23
@property
def b(self):
return 2 * self.a
t = te()
In [4]: t.a
Out[4]: 23
In [5]: t.b
Out[5]: 46
#works asexpected so far, now let's have a look into t.__dict__
In [6]: t.__dict__
Out[6]: {'a': 23}
- b does not show up.
Could anyone please explain me why this does not work / how to get b
into .__dict__ / hint me to an explanation?
Thanks a lot in advance!
Cheers,
Ulrich
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Re: Class: @property - .__dict__
On Fri, 16 Dec 2011 00:52:11 -0800, Ulrich wrote: Good morning, I wonder if someone could please help me out with the @property function as illustrated in the following example. class te(): def __init__(self): self.a = 23 @property def b(self): return 2 * self.a [...] Could anyone please explain me why this does not work / how to get b into .__dict__ / hint me to an explanation? b is a property object. Like any other assignment inside the body of the class, it is shared across all instances, so you won't find it in the instance's personal dict. You will find it in the shared class dict. t.__dict__['b'] # not found te.__dict__['b'] # will return the property object (By the way: it is the usual convention to start the name of a class with initial capital, so Te would be a better name.) To get something into the instance dict, you need to assign it onto the instance: t.x = 42 # puts 'x':42 into t.__dict__ -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Class: @property - .__dict__
On Dec 16, 10:03 am, Steven D'Aprano steve +comp.lang.pyt...@pearwood.info wrote: On Fri, 16 Dec 2011 00:52:11 -0800, Ulrich wrote: Good morning, I wonder if someone could please help me out with the @property function as illustrated in the following example. class te(): def __init__(self): self.a = 23 @property def b(self): return 2 * self.a [...] Could anyone please explain me why this does not work / how to get b into .__dict__ / hint me to an explanation? b is a property object. Like any other assignment inside the body of the class, it is shared across all instances, so you won't find it in the instance's personal dict. You will find it in the shared class dict. t.__dict__['b'] # not found te.__dict__['b'] # will return the property object (By the way: it is the usual convention to start the name of a class with initial capital, so Te would be a better name.) To get something into the instance dict, you need to assign it onto the instance: t.x = 42 # puts 'x':42 into t.__dict__ -- Steven Hi Steven, Thanks a lot for your quick and helpful answer! This would imply that I have to search in the dict of the class and the dict of the instance. - works nicely. I wonder if there is somewhere a merge of the two already available. In the meantime, I came across dir() In [7]: dir(t) Out[7]: ['__doc__', '__init__', '__module__', 'a', 'b'] This seems to return 'a' and 'b', but now crashes @property def attributelist(self): # find all attributes to the class that are of type numpy arrays: return [attr for attr in self.__dict__ if isinstance(getattr(self, attr), numpy.ndarray)] -- http://mail.python.org/mailman/listinfo/python-list
Re: Class: @property - .__dict__
On Dec 16, 10:11 am, Ulrich ulrich.do...@gmail.com wrote: On Dec 16, 10:03 am, Steven D'Aprano steve +comp.lang.pyt...@pearwood.info wrote: On Fri, 16 Dec 2011 00:52:11 -0800, Ulrich wrote: Good morning, I wonder if someone could please help me out with the @property function as illustrated in the following example. class te(): def __init__(self): self.a = 23 @property def b(self): return 2 * self.a [...] Could anyone please explain me why this does not work / how to get b into .__dict__ / hint me to an explanation? b is a property object. Like any other assignment inside the body of the class, it is shared across all instances, so you won't find it in the instance's personal dict. You will find it in the shared class dict. t.__dict__['b'] # not found te.__dict__['b'] # will return the property object (By the way: it is the usual convention to start the name of a class with initial capital, so Te would be a better name.) To get something into the instance dict, you need to assign it onto the instance: t.x = 42 # puts 'x':42 into t.__dict__ -- Steven Hi Steven, Thanks a lot for your quick and helpful answer! This would imply that I have to search in the dict of the class and the dict of the instance. - works nicely. I wonder if there is somewhere a merge of the two already available. In the meantime, I came across dir() In [7]: dir(t) Out[7]: ['__doc__', '__init__', '__module__', 'a', 'b'] This seems to return 'a' and 'b', but now crashes @property def attributelist(self): # find all attributes to the class that are of type numpy arrays: return [attr for attr in self.__dict__ if isinstance(getattr(self, attr), numpy.ndarray)] hi again, I must have hit the send accidently before finishing. This attributelist should return me all attributes of type numpy.ndarry. if I replace it to def attributelist(self): # find all attributes to the class that are of type numpy arrays: return [attr for attr in dir(self) if isinstance(getattr(self, attr), numpy.ndarray)] it crashes going into some kind of endless loop. Do you happen to have any idea? thanks again! cheers, ulrich -- http://mail.python.org/mailman/listinfo/python-list
Re: AttributeError in with statement (3.2.2)
On Thu, 15 Dec 2011 19:39:17 -0500, Terry Reedy wrote: [...] After reading your post, I think I have worked out where our disagreement lines: you think that bound methods and instance methods are not the same thing, and that a function defined inside a class is different from a function outside of a class. For example, you say: If so, the output is a *bound method*. In your example above, func is not an instance method and obj is not a bound method. It is simply an partially evaluated curried function or if you prefer, a bound function. Take you pick, or make up your own term, but it is NOT an instance method, and later on: So what are methods? In Python, methods are wrappers around functions which automatically pass the instance to the inner function object. These are bound methods. The instance methods are the functions wrapped. I am afraid you are mistaken. What you say may very well apply to other languages, but in Python, def creates functions no matter where you execute it. Always and without exception. I admit to an earlier mistake: I thought that conversion from function to method occurred once, when the class statement was executed, but I was mistaken. Re-reading Raymond Hettinger's excellent article on the descriptor protocol reminded me that methods are created on an as-needed basis, at runtime. Back to methods and def. So let's see what happens in Python 3.1: def spam(self): # Clearly a function. ...pass ... class K(object): ... def ham(self): # Allegedly an instance method ... pass ... According to your various statements, spam is a function and ham is an instance method. Merely storing a outside function inside a class doesn't create an instance method, it creates what you call a bound method (although I'm unclear what you think the difference is). So let's see what happens when we compare an alleged bound method that is not an instance method with an actual instance method: K.spam = spam type(K.spam) is type(K.ham) True Their types are identical. We get the same thing when we compare an actual function with a function object created inside a class, which you claim is actually an instance method: type(spam) is type(K.__dict__['ham']) # Bypass descriptor protocol True Nor is there any difference in type between bound and unbound methods: they are both instance methods differing only in whether or not they have the first argument self available. Bound is an adjective, not part of the type: small method, obfuscated method, buggy method, or bound method. Python 3 no longer uses unbound methods, since they are functionally identical to the unwrapped function, so this snippet is from Python 2.6: py k = K() py type(k.ham) is type(K().ham) # bound vs bound True py type(k.ham) is type(K.ham) # bound vs unbound True In Python, instance methods are wrappers around function objects; they are created on call, and generally do not exist *anywhere* until needed, or if you store a reference to them. k = K() a = k.ham b = k.ham a is b False Under normal circumstances, the only persistent object is the function, which you can extract from the (class or instance) __dict__ or the method wrapper: a.__func__ is K.__dict__['ham'] True Methods are created by the descriptor protocol: when you use the normal a.b syntax to access K.__dict__['ham'], the metaclass calls the __get__ method of function ham. If you call it from an instance, you get a method object bound to that instance. If you call it from the class, in Python 2 you get a method object not bound to an instance, in Python 3 you get the function without a wrapper. [Aside: class methods and static methods also work the same way, via __get__ and the descriptor protocol, but behave differently. Class methods reuse the instance method type, which is somewhat confusing, and static methods just return the function.] So, what the hell does all this mean in practice? Most of the time, absolutely nothing. That's why I started this discussion with the disclaimer that I didn't think it was worth changing the (not quite right) definition of method you originally quoted. Most of the time, we only access methods via the instance.method syntax, which gives us an instance method. By the principle that if it quacks like a duck and swims like a duck, it is good enough to call it a duck, I'm happy to agree that ham here is a method: class K: def ham(self): pass That covers 99% of all use-cases and is good enough for most situations. But the OP ran into one of those edge cases in the 1%, where things are not so simple. He was attempting to create an instance method called __exit__ and store it in the instance __dict__ instead of the class __dict__. This is a perfectly reasonable thing to do, but there are two gotchas to it: * The descriptor protocol doesn't get used for instance lookups. That's why you can't stick properties in an instance,
Re: Class: @property - .__dict__
Ulrich wrote: if I replace it to def attributelist(self): # find all attributes to the class that are of type numpy arrays: return [attr for attr in dir(self) if isinstance(getattr(self, attr), numpy.ndarray)] it crashes going into some kind of endless loop. Do you happen to have any idea? dir(self) finds an attribute named attributelist, getattr(self, attributelist) then tries to calculate the value of that attribute, invokes dir(self) which finds an attribute named attributelist and so on ad infinitum or the stack overflows. Try (untested) @property def attributelist(self): return [attr for attr in dir(self) if attr != attributelist and isinstance(getattr(self, attr), numpy.ndarray)] to avoid the infinite recursion. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class: @property - .__dict__
Am 16.12.2011 09:52 schrieb Ulrich: Could anyone please explain me why this does not work / how to get b into .__dict__ / hint me to an explanation? b is not a data element of the particular instance, but it lives in the class. It is, roughly spoken, a kind of method, just to be used without calling. These things are called data descriptors (http://docs.python.org/reference/datamodel.html#descriptors). t.b is internally reflected to te.__dict__['b'].__get__(t, te) in order to call the __get__ method of the property object. This is done on every call and the value is, in your case, derived from the instance value a. HTH, Thomas -- http://mail.python.org/mailman/listinfo/python-list
modifying a time.struct_time
Hi! I'm trying to create a struct_time that is e.g. one year ahead or a month back in order to test some parsing/formatting code with different dates. Now, the straightforward approach is t = time.localtime() t.tm_year += 1 This fails with TypeError: readonly attribute. This kind-of makes sense, as an immutable object allows you to use it as key in a dict. The second approach is this: l = list(t) # convert to a sequence l[0] += 1 # increment year t = time.struct_time(l) # convert to a struct_time This works but is ugly, because the code relies on the order inside the list and uses magic numbers to access them. The order is AFAICT not accessible programmatically but only documented, and not even in a way that makes clear that it is part of the API and as such actualy guaranteed. I could try to assert that the indices match using if l[0] is t.tm_year, but this is still ugly. The next approach I tried was to simply create a derived class: class my_time(time.struct_time): pass This fails again with TypeError: Error when calling the metaclass bases, type 'time.struct_time' is not an acceptable base type. I could try to encapsulate a struct_time and delegate attribute access to it in order to do this, but it also seems overkill. Also, using an immutable type as a baseclass and delegating access to members seems like hackery to me, prone to fail in situations where it is least expected. Then I tried duck typing. If it quacks like a duck, it better not be a crocodile! This looks like this: struct my_time(object): pass t = my_time() t.tm_year = 2012 t.tm_month = 12 t.tm... # other fields accordingly time.mktime(t) This fails with TypeError: argument must be 9-item sequence, not my_time. I thought about using a collections.namedtuple, because a namedtuple is a tuple and therefore also a sequence, but that only leads me back to the problem that time.mktime() takes a sequence and the order of the sequence is not accessible programmatically. A last approach was to convert the thing to a dict and back. Alas, there is no conversion to a dict, otherwise d = dict(t) d['tm_year'] += 1 t = time.struct_time(d) would have been a straightforward approach. Does anyone have a suggestion how to solve this elegantly and pythonically? Also, what I'm wondering is if the lack of a clear way should be considered a bug or not. Cheers! Uli -- http://mail.python.org/mailman/listinfo/python-list
Re: modifying a time.struct_time
Hi, Easiest way is to change the time to seconds, add as many seconds as a year/month/week/day/hour/minutes represent and then transform it back. E.g. time.time() 1324031491.026137 time.time() + 3600 # Add an hour 1324035105.082003 time.gmtime(time.time() + 3600) time.struct_time(tm_year=2011, tm_mon=12, tm_mday=16, tm_hour=11, tm_min=31, tm_sec=57, tm_wday=4, tm_yday=350, tm_isdst=0) On 16 December 2011 10:45, Ulrich Eckhardt ulrich.eckha...@dominolaser.com wrote: Hi! I'm trying to create a struct_time that is e.g. one year ahead or a month back in order to test some parsing/formatting code with different dates. Now, the straightforward approach is t = time.localtime() t.tm_year += 1 This fails with TypeError: readonly attribute. This kind-of makes sense, as an immutable object allows you to use it as key in a dict. The second approach is this: l = list(t) # convert to a sequence l[0] += 1 # increment year t = time.struct_time(l) # convert to a struct_time This works but is ugly, because the code relies on the order inside the list and uses magic numbers to access them. The order is AFAICT not accessible programmatically but only documented, and not even in a way that makes clear that it is part of the API and as such actualy guaranteed. I could try to assert that the indices match using if l[0] is t.tm_year, but this is still ugly. The next approach I tried was to simply create a derived class: class my_time(time.struct_time): pass This fails again with TypeError: Error when calling the metaclass bases, type 'time.struct_time' is not an acceptable base type. I could try to encapsulate a struct_time and delegate attribute access to it in order to do this, but it also seems overkill. Also, using an immutable type as a baseclass and delegating access to members seems like hackery to me, prone to fail in situations where it is least expected. Then I tried duck typing. If it quacks like a duck, it better not be a crocodile! This looks like this: struct my_time(object): pass t = my_time() t.tm_year = 2012 t.tm_month = 12 t.tm... # other fields accordingly time.mktime(t) This fails with TypeError: argument must be 9-item sequence, not my_time. I thought about using a collections.namedtuple, because a namedtuple is a tuple and therefore also a sequence, but that only leads me back to the problem that time.mktime() takes a sequence and the order of the sequence is not accessible programmatically. A last approach was to convert the thing to a dict and back. Alas, there is no conversion to a dict, otherwise d = dict(t) d['tm_year'] += 1 t = time.struct_time(d) would have been a straightforward approach. Does anyone have a suggestion how to solve this elegantly and pythonically? Also, what I'm wondering is if the lack of a clear way should be considered a bug or not. Cheers! Uli -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
On Dec 16, 3:58 am, MRAB pyt...@mrabarnett.plus.com wrote: On 16/12/2011 02:14, alex23 wrote: Eelcohoogendoorn.ee...@gmail.com wrote: To tie it back in with python language design; all the more reason not to opt for pseudo-backwards compatibility. If python wants a remainder function, call it 'remainder'. Not 'rem', not 'mod', and certainly not '%'. Python has def, del, int, str, len, and so on. rem or mod (Ada has both, I believe) would be in keeping with the language. def and del are keywords, and thus in another league. Having shorthand notation for types is somewhat defensible, though I believe I would prefer a more verbose form there too; how often to you encounter these in python anyway? len is a bit of an eeysore to me too; I understand having it as a builtin is a matter of optimization or something, but I do wish we would be given the option of just saying list.length Good luck with the PEP. Its the more pythonic way; a self-describing name, rather than poorly defined or poorly understood cryptology. Although practicality beats purity. I'm still utterly agog that anyone finds the operator % confusing. In financial circles it could be an operator for calculating percentages, eg. 5 % x would be 5 percent of x. It's an oddity, but an established one. :-) Well yes, thats the only argument ive heard so far that resonated with me. These syntax details are not a very big deal, and backwards compatibility with yourself is quite a big deal. Its nice to keep 'what ought to have been done' and 'what ought we to do' seperate in such discussions. Im not sure we ought to change these syntax details (I mean relating to mod and such), but I am quite sure of what I would have done if I could go back in time. -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
On Dec 16, 6:30 am, alex23 wuwe...@gmail.com wrote: On Dec 16, 3:01 pm, Chris Angelico ros...@gmail.com wrote: And I would be most sorry to see % renamed to mod in Python. Hello, %s! My favourite number is %d. mod (Fred,42) # This just looks wrong. Finally we can give this operator a more fitting name - I propose 'inject' - and put an end to this insane desire to leverage off pre- existing knowledge of other languages. Furthermore, I suggest that no two languages should ever have identical semantics, just to avoid potential confusion. New concepts for all! Dont get me started on that one. Its that I never work with strings... 'leverage of pre-existing knowledge'... I would hardly call the particular names of functions the knowledge about a language. The only argument that bears any weight with me is backwards compatibility with itself. Pseudo-backwards compatibility with other languages, I couldnt not care less for. -- http://mail.python.org/mailman/listinfo/python-list
Re: modifying a time.struct_time
On Fri, 16 Dec 2011 10:45:22 +0100, Ulrich Eckhardt wrote: Hi! I'm trying to create a struct_time that is e.g. one year ahead or a month back in order to test some parsing/formatting code with different dates. [...] The second approach is this: l = list(t) # convert to a sequence l[0] += 1 # increment year t = time.struct_time(l) # convert to a struct_time This works but is ugly, because the code relies on the order inside the list and uses magic numbers to access them. The order is AFAICT not accessible programmatically but only documented, and not even in a way that makes clear that it is part of the API and as such actualy guaranteed. I could try to assert that the indices match using if l[0] is t.tm_year, but this is still ugly. Feel free to propose a feature enhancement to time.struct_time, but the order of the fields is stable and won't change. So ugly or not, that way is guaranteed to work. [...] Then I tried duck typing. If it quacks like a duck, it better not be a crocodile! This looks like this: struct my_time(object): pass struct? [...] Does anyone have a suggestion how to solve this elegantly and pythonically? Also, what I'm wondering is if the lack of a clear way should be considered a bug or not. Not a bug, but it does seem a very old and inelegant API more suited to hairy C programmers gathered around a smokey fire in a cave chewing on old dinosaur bones, and not worthy of space-age Python coders flying around on anti-gravity belts. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: modifying a time.struct_time
On Fri, Dec 16, 2011 at 8:45 PM, Ulrich Eckhardt ulrich.eckha...@dominolaser.com wrote: I'm trying to create a struct_time that is e.g. one year ahead or a month back in order to test some parsing/formatting code with different dates. Do you need it to be one exact calendar year, or would it make sense to add/subtract integers from a Unix time? t = time.time() + 365*86400 # Not actually a year ahead, it's 365 days ahead t = time.localtime(t) # if you want a struct_time ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: modifying a time.struct_time
On 16/12/2011 10:44, Steven D'Aprano wrote: [ on time.struct_time ] Not a bug, but it does seem a very old and inelegant API more suited to hairy C programmers gathered around a smokey fire in a cave chewing on old dinosaur bones, and not worthy of space-age Python coders flying around on anti-gravity belts. +1 QOTW TJG -- http://mail.python.org/mailman/listinfo/python-list
GlobalLogic PYTHON/JAVA positions
Hi All , Trust you doing well.. GlobalLogic is looking for highly skilled *Python Developers/Sr.Developers* , *JAVA DEVELOPERS/Sr. Developers* for one of our strategic engagements with * GOOGLE. * Following are the details: *Python Developer(s)/Sr. Developers* Experience: 1-5 Yrs Min Qualification: BS/BE/B.Tech/MCA Regular Job Location: Client site- Gurgaon (India) Google office Positions: 20 * * *Requisites:* - * * OOPS concepts in Python - Exposure to python as a language , not only as a script - Good knowledge of File handling and XML parsing -Good to have experience in Multithreading in python. - Usage of inbuilt data types. -Implementation Of various design patterns - Should have Worked On python specific packages - Should have Worked On python specific frameworks like django, zope, - Exposure to middlewares, decorators, etc. - He should have worked on web apps instead of desktop apps. For Python: Send updated CV to richa.si...@globallogic.com * * *JAVA Positions: * * * *Min Qualification*: BS/BE/B.Tech/MCA or equivalent. *Location* – Client site- Gurgaon (India) Google office *Positions: 10* *Experience*: Total work exp should be 2 - 5 yrs - Work experience and relevant experience in internet architecture and software development. - Fluency in at least two of the following languages: Java, JavaScript. - Expertise in object-oriented programming and design patterns (primarily MVC). - Hands on experience in database design, SQL and any ORM tool like Hibernate/JDO etc. - Experience in TDD based developmen. *Desired Skills*: - Innovativeness; ability to think outside the box . - Creativity and problem-solving ability . - Very good communication skills; must be able to gather requirements from potential users and discuss the requirements effectively with a technical team of developers . - Previous experience in developing web applications will be an added advantage. Working knowledge of linux environment is a plus. - Previous experience of working with Google tools/gadgets is a big plus. For Java : Send updated CV to ankit.bans...@globallogic.com * Do visit* www.globallogic.com* **Share this mail with your friends, alumni groups,communities etc., spread the great opportunity :) * -- Regards, Richa Sinha | Talent Acquisition *Leaders in Software RD Services* *www.globallogic.com* http://www.globallogic.com/ ARGENTINA |CHINA | INDIA | ISRAEL | UKRAINE | UK | USA Office: +91-120-406-2378 http://www.youtube.com/watch?v=V4pwY800TII -- http://mail.python.org/mailman/listinfo/python-list
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http;//123maza.com/48/moon670/ -- http://mail.python.org/mailman/listinfo/python-list
merging argparse parsers
I would like to have something like
merged_parser = LoggingParser() + OtherParser()
Which should create an argument parser with all the options composed.
Now for that I think I would need to subclass the argument, and something
fancy with the overloading.
The problem is that apparently there is no Argument class, but add_argument
just change the object internal data structures.
So the only alternative I see now is to do something like:
def add_project_argument(parser):
parser.add_argument('project_path',
help='paths of the project to run')
which is not very neat and modifies the object in place.
Any other ideas?
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RE: Localhost client-server simple ssl socket test program problems
To: python-list@python.org From: li...@cheimes.de Subject: Re: Localhost client-server simple ssl socket test program problems Date: Thu, 15 Dec 2011 20:45:43 +0100 Am 15.12.2011 20:09, schrieb Yang Chun-Kai: Server side error: File views.py, line 17, in module connstream = ssl.wrap_socket(newsocket, server_side=True, certfile=/etc/home/ckyang/PHA/testsslsocket/mypha.crt, keyfile=/etc/home/ckyang/PHA/testsslsocket/mypha.key, ssl_version=ssl.PROTOCOL_SSLv23) File /usr/lib/python2.7/ssl.py, line 344, in wrap_socket ciphers=ciphers) File /usr/lib/python2.7/ssl.py, line 119, in __init__ ciphers) ssl.SSLError: [Errno 336265218] _ssl..c:347: error:140B0002:SSL routines:SSL_CTX_use_PrivateKey_file:system lib This error is most likely caused by an encrypted private key. Python's SSL lib doesn't support encrypted private keys for sockets. You can encrypt the private key with I generate the server private key with openssl genrsa -out mypha.key 2048.But this seems the standard command to do it.How do I get the private key without encrypted ?Or should I always do this and encrypt it again to get it decrypted ?If I use the encrypted key and .csr to produce my certificate will that be different from decrypted key?Thanks.Kay openssl rsa -in /etc/home/ckyang/PHA/testsslsocket/mypha.key -out /etc/home/ckyang/PHA/testsslsocket/mypha-nopasswd.key Christian -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Make a small function thread safe
Hey guys,
I have a C++ function that I'd like to replicate (as closely as
possible) in Python. Here's an example:
107 void increment_counter( unsigned int counter )
108 {
109 boost::mutex::scoped_lock lock( counter_lock );
110 ++counter;
111 }
A thread locks the function on entrance and then releases it on exit.
What is the equivalent way to do this in Python?
Many thanks!
Brad
--
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Re: Make a small function thread safe
On Fri, 2011-12-16 at 05:21 -0800, Brad Tilley wrote:
107 void increment_counter( unsigned int counter )
108 {
109 boost::mutex::scoped_lock lock( counter_lock );
110 ++counter;
111 }
with counter_lock:
counter += 1
... where counter_lock is a threading.Lock instance.
(see docs for the threading module)
Tim
--
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Re: modifying a time.struct_time
Am 16.12.2011 10:45, schrieb Ulrich Eckhardt: I'm trying to create a struct_time that is e.g. one year ahead or a month back in order to test some parsing/formatting code with different dates. There is something I stumbled across that helps and that is the datetime module, which seems more reasonably pythonic, and which allows operations on dates like adding a Concerning the idea to use seconds, I'd rather not, because already the number of seconds per minute ranges from 60 to 62, and it doesn't get better with things like months (28...31 days), years (365...366 days) and all other types built upon them. Considering the question if the current state is buggy, I'm definitely +1 on it. I do understand that this API is not going to change, but explicitly documenting in help(time) that the order is fixed and possibly making the order programmatically available are not changes but useful additions, IMHO. Also, conversion from/to a dict and perhaps a link to the datetime module would have saved me some futile attempts. Thanks to all responders, I wish you a happy weekend! Uli -- http://mail.python.org/mailman/listinfo/python-list
Re: Make a small function thread safe
On Fri, Dec 16, 2011 at 8:33 AM, Tim Wintle tim.win...@teamrubber.comwrote:
On Fri, 2011-12-16 at 05:21 -0800, Brad Tilley wrote:
107 void increment_counter( unsigned int counter )
108 {
109 boost::mutex::scoped_lock lock( counter_lock );
110 ++counter;
111 }
with counter_lock:
counter += 1
... where counter_lock is a threading.Lock instance.
(see docs for the threading module)
So something like this then:
import threading
shared_container = []
lock = threading.Lock()
class thread_example( threading.Thread ):
def __init__( self ):
threading.Thread.__init__ (self)
def run(t):
lock
shared_container.append(t.name)
# main
threads = []
for i in xrange(10):
thread = thread_example()
threads.append(thread)
for thread in threads:
thread.start()
for item in shared_container:
print item
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Re: modifying a time.struct_time
On Sat, Dec 17, 2011 at 12:32 AM, Ulrich Eckhardt ulrich.eckha...@dominolaser.com wrote: Concerning the idea to use seconds, I'd rather not, because already the number of seconds per minute ranges from 60 to 62, and it doesn't get better with things like months (28...31 days), years (365...366 days) and all other types built upon them. Right, which is why I asked how important the difference between 365 days and 1 year is. Obviously if your goal is one entire calendar year, then you don't want to duplicate the work of figuring out how many seconds that is. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Make a small function thread safe
On Fri, Dec 16, 2011 at 9:24 AM, Brad Tilley kj4...@gmail.com wrote:
On Fri, Dec 16, 2011 at 8:33 AM, Tim Wintle tim.win...@teamrubber.comwrote:
On Fri, 2011-12-16 at 05:21 -0800, Brad Tilley wrote:
107 void increment_counter( unsigned int counter )
108 {
109 boost::mutex::scoped_lock lock( counter_lock );
110 ++counter;
111 }
with counter_lock:
counter += 1
... where counter_lock is a threading.Lock instance.
(see docs for the threading module)
So something like this then:
import threading
shared_container = []
lock = threading.Lock()
class thread_example( threading.Thread ):
def __init__( self ):
threading.Thread.__init__ (self)
def run(t):
lock
shared_container.append(t.name)
# main
threads = []
for i in xrange(10):
thread = thread_example()
threads.append(thread)
for thread in threads:
thread.start()
for item in shared_container:
print item
Or perhaps run should look like this instead:
def run(t):
lock.acquire()
shared_container.append(t.name)
lock.release()
That seems a bit barbaric to me, not sure.
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Re: Make a small function thread safe
On Fri, 2011-12-16 at 09:24 -0500, Brad Tilley wrote: So something like this then: import threading shared_container = [] lock = threading.Lock() class thread_example( threading.Thread ): def __init__( self ): threading.Thread.__init__ (self) def run(t): lock shared_container.append(t.name) should be: def run(t): with lock: shared_container.append(t.name) (or lock.acquire() and lock.release() as you mentioned) # main threads = [] for i in xrange(10): thread = thread_example() threads.append(thread) for thread in threads: thread.start() you'll either need to lock again here, or join each thread: for thread in threads: thread.join() for item in shared_container: print item Tim -- http://mail.python.org/mailman/listinfo/python-list
Re: ERP with Supply chain management (incl. POS) and Customer relationship management ??? What's available?
On 2011-12-16, Gregory Ewing greg.ew...@canterbury.ac.nz wrote: On Thu, Dec 15, 2011 at 5:54 AM, Anurag Chourasia anurag.choura...@gmail.com wrote: I am building a POS/CRM (Loyalty Management) system as well. Is it just me, or does the phrase Loyalty Management have a faintly ominous ring to it? Yea, sounds a bit like Newspeak -- maybe it's what the secret police do under a dictatorship. -- Grant Edwards grant.b.edwardsYow! It's some people at inside the wall! This is gmail.combetter than mopping! -- http://mail.python.org/mailman/listinfo/python-list
Re: Make a small function thread safe
On Dec 16, 9:36 am, Tim Wintle tim.win...@teamrubber.com wrote: should be: def run(t): with lock: shared_container.append(t.name) (or lock.acquire() and lock.release() as you mentioned) Thanks Tim. The with statement is closer to the C++ code (IMO) more so than the explicit acquire() and release() so I'll use that approach. I appreciate your advice. Brad -- http://mail.python.org/mailman/listinfo/python-list
Re: ERP with Supply chain management (incl. POS) and Customer relationship management — What's available?
On 12/15/2011 6:43 AM Alec Taylor said... On Thu, Dec 15, 2011 at 5:54 AM, Anurag Chourasia anurag.choura...@gmail.com wrote: Hi Alec, I am building a POS/CRM (Loyalty Management) system as well. So far, the best I could find to use as a base OpenERP? Emile -- http://mail.python.org/mailman/listinfo/python-list
Re: Class: @property - .__dict__
On Fri, Dec 16, 2011 at 2:32 AM, Peter Otten __pete...@web.de wrote: Ulrich wrote: if I replace it to def attributelist(self): # find all attributes to the class that are of type numpy arrays: return [attr for attr in dir(self) if isinstance(getattr(self, attr), numpy.ndarray)] it crashes going into some kind of endless loop. Do you happen to have any idea? dir(self) finds an attribute named attributelist, getattr(self, attributelist) then tries to calculate the value of that attribute, invokes dir(self) which finds an attribute named attributelist and so on ad infinitum or the stack overflows. Try (untested) @property def attributelist(self): return [attr for attr in dir(self) if attr != attributelist and isinstance(getattr(self, attr), numpy.ndarray)] to avoid the infinite recursion. Or remove attributelist from the class (it feels more like a generic function than a class property to me) or make it a method instead of a property. -- http://mail.python.org/mailman/listinfo/python-list
re.sub(): replace longest match instead of leftmost match?
According to the documentation on re.sub(), it replaces the leftmost matching pattern. However, I want to replace the *longest* matching pattern, which is not necessarily the leftmost match. Any suggestions? I'm working with IPv6 CIDR strings, and I want to replace the longest match of (:|$)+ with :. But when I use re.sub() it replaces the leftmost match, even if there is a longer match later in the string. I'm also looking for a regexp that will remove leading zeroes in each four-digit group, but will leave a single zero if the group was all zeroes. Thanks! -- John Gordon A is for Amy, who fell down the stairs gor...@panix.com B is for Basil, assaulted by bears -- Edward Gorey, The Gashlycrumb Tinies -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
You could use re.finditer to find the longest match, and then replace it manually by hand (via string slicing). (a match is the longest if (m.end() - m.start()) is the largest -- so, max(re.finditer(...), key=lambda m: (m.end() = m.start())) -- Devin P.S. does anyone else get bothered by how it's slice.start and slice.stop, but match.start() and match.end() ? On Fri, Dec 16, 2011 at 11:49 AM, John Gordon gor...@panix.com wrote: According to the documentation on re.sub(), it replaces the leftmost matching pattern. However, I want to replace the *longest* matching pattern, which is not necessarily the leftmost match. Any suggestions? I'm working with IPv6 CIDR strings, and I want to replace the longest match of (:|$)+ with :. But when I use re.sub() it replaces the leftmost match, even if there is a longer match later in the string. I'm also looking for a regexp that will remove leading zeroes in each four-digit group, but will leave a single zero if the group was all zeroes. Thanks! -- John Gordon A is for Amy, who fell down the stairs gor...@panix.com B is for Basil, assaulted by bears -- Edward Gorey, The Gashlycrumb Tinies -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
On 16/12/2011 16:49, John Gordon wrote: According to the documentation on re.sub(), it replaces the leftmost matching pattern. However, I want to replace the *longest* matching pattern, which is not necessarily the leftmost match. Any suggestions? I'm working with IPv6 CIDR strings, and I want to replace the longest match of (:|$)+ with :. But when I use re.sub() it replaces the leftmost match, even if there is a longer match later in the string. I'm also looking for a regexp that will remove leading zeroes in each four-digit group, but will leave a single zero if the group was all zeroes. How about this: result = re.sub(r\b0+(\d)\b, r\1, string) -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
On Dec 16, 3:25 pm, Eelco hoogendoorn.ee...@gmail.com wrote: Pseudo-backwards compatibility with other languages, I couldnt not care less for. Double negations n Goedelian situations have interesting implications (tho here its triple) -- http://mail.python.org/mailman/listinfo/python-list
Making the case for typed lists/iterators in python
I realize this has been discussed in the past, I hope that I am presenting a slightly different take on the subject that will prove interesting. This is primarily motivated by my annoyance with using comprehensions in certain circumstances. Currently, if you want to perform successive transformations on the elements of a list, a couple of options: 1. Successive comprehensions: L2 = [X(e) for e in L1] L3 = [Y(e) for e in L2] L4 = [Z(e) for e in L3] or L2 = [e.X() for e in L1] This gets the job done and gives you access to all the intermediate values, but isn't very succinct, particularly if you are in the habit of using informative identifiers. 2. One comprehension: L2 = [Z(X(Y(e))) for e in L1] or L2 = [e.X().Y().Z() for e in L1] This gets the job done, but doesn't give you access to all the intermediate values, and tends to be pretty awful to read. Having typed lists let you take preexisting string/int/etc methods and expose them in a vectorized context and provides an easy way for developers to support both vectors and scalars in a single function (you could easily fix other people's functions dynamically to support both). Additionally, typed lists/iterators will allow improved code analysis and optimization. The PyPy people have already stated that they are working on implementing different strategies for lists composed of a single type, so clearly there is already community movement in this direction. Just compare the above examples to their type-aware counterparts: L2 = X(L1) L2 = L1.X() L2 = Z(Y(X(L1))) L2 = L1.X().Y().Z() Also, this would provide a way to clean up stuff like: \n.join(l.capitalize() for l in my_string.split(\n)) into: my_string.split(\n).capitalize().join_this(\n) Before anyone gets up in arms at the idea of statically typed python, what I am suggesting here would be looser than that. Basically, I believe it would be a good idea in instances where it is known that a list of single type is going to be returned, to return a list subclass (for example, StringList, IntegerList, etc). To avoid handcuffing people with types, the standard list modification methods could be hooked so that if an object of an incorrect type is placed in the list, a warning is raised and the list converts to a generic object list. The only stumbling block is that you can't use __class__ to convert from stack types to heap types in CPython. My workaround for this would be to have a factory that creates generic List classes, modifying the bases to produce the correct behavior. Then, converting from a typed list to a generic object list would just be a matter of removing a member from the bases for a class. This of course basically kills the ability to perform type specific list optimization in CPython, but that isn't necessarily true for other implementations. The additional type information would be preserved for code analysis in any case. The case would be even simpler for generators and other iterators, as you don't have to worry about mutation. I'd like to hear people's thoughts on the subject. Currently we are throwing away useful information in many cases that could be used for code analysis, optimization and simpler interfaces. I believe that typed lists that get demoted to normal lists with a warning on out of type operations preserve this information while providing complete backwards compatibility and freedom. Nathan -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
On Fri, Dec 16, 2011 at 10:36 AM, MRAB pyt...@mrabarnett.plus.com wrote: On 16/12/2011 16:49, John Gordon wrote: According to the documentation on re.sub(), it replaces the leftmost matching pattern. However, I want to replace the *longest* matching pattern, which is not necessarily the leftmost match. Any suggestions? I'm working with IPv6 CIDR strings, and I want to replace the longest match of (:|$)+ with :. But when I use re.sub() it replaces the leftmost match, even if there is a longer match later in the string. I'm also looking for a regexp that will remove leading zeroes in each four-digit group, but will leave a single zero if the group was all zeroes. How about this: result = re.sub(r\b0+(\d)\b, r\1, string) Close. pattern = r'\b0+([1-9a-f]+|0)\b' re.sub(pattern, r'\1', string, flags=re.IGNORECASE) Cheers, Ian -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Interpreter Error with PyDev (Eclipse IDE)
It seems you have a version of Python 2.5 in your system and when starting up Python 3.2.2 it's getting things from 2.5 (this would probably also happen on the command line). The usual suspect is that you defined a PYTHONROOT variable which is pointing to Python 2.5 and not to the python you're using... Cheers, Fabio On Thu, Dec 15, 2011 at 10:20 PM, Joshua Jodrey jdjod...@yahoo.com wrote: Hi, This is my first email to this list, so I apologize if there's a better mailing-list for this type of question. I'm looking to get started with python development, so I downloaded Python 3.2.2 and PyDev IDE for Eclipse. When I go to configure my interpreter for a new python project, Windows gives me the following error: python.exe has stopped working and then Eclipse shows Error getting info on interpreter See error log for details. No output was in the standard output when trying to create the interpreter info. The error output contains:Fatal Python error: Py_Initialize: unable to load the file system codec File C:\csvn\Python25\\lib\encodings\__init__.py, line 120 raise CodecRegistryError,\ ^ SyntaxError: invalid syntax This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Does anybody have any idea what this means or what I'm doing wrong? I've tried re-installing Python, but still can't get it to work. And again, if I'm in the wrong place, please direct me to the proper mailing-list or forum. Thanks! Josh P.S. I'm not subscribed to this mailer, so please include me in your replies! -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
On Fri, Dec 16, 2011 at 10:57 AM, Ian Kelly ian.g.ke...@gmail.com wrote:
On Fri, Dec 16, 2011 at 10:36 AM, MRAB pyt...@mrabarnett.plus.com wrote:
On 16/12/2011 16:49, John Gordon wrote:
According to the documentation on re.sub(), it replaces the leftmost
matching pattern.
However, I want to replace the *longest* matching pattern, which is
not necessarily the leftmost match. Any suggestions?
I'm working with IPv6 CIDR strings, and I want to replace the longest
match of (:|$)+ with :. But when I use re.sub() it replaces
the leftmost match, even if there is a longer match later in the string.
I'm also looking for a regexp that will remove leading zeroes in each
four-digit group, but will leave a single zero if the group was all
zeroes.
How about this:
result = re.sub(r\b0+(\d)\b, r\1, string)
Close.
pattern = r'\b0+([1-9a-f]+|0)\b'
re.sub(pattern, r'\1', string, flags=re.IGNORECASE)
Doh, that's still not quite right.
pattern = r'\b0{1,3}([1-9a-f][0-9a-f]*|0)\b'
re.sub(pattern, r'\1', string, flags=re.IGNORECASE)
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Re: Making the case for typed lists/iterators in python
In article mailman.3739.1324057724.27778.python-l...@python.org, Nathan Rice nathan.alexander.r...@gmail.com wrote: I'd like to hear people's thoughts on the subject. Currently we are throwing away useful information in many cases that could be used for code analysis, optimization and simpler interfaces. Most of this was TL:DNR, but I will admit I often wish for a better way to log intermediate values. For example, a common pattern in the code I'm working with now is functions that end in: return [Foo(x) for x in bunch_of_x_thingies] When something goes amiss and I want to debug the problem, I often transform that into: temp = [Foo(x) for x in bunch_of_x_thingies] logger.debug(temp) return temp It would be convenient to be able to get at and log the intermediate value without having to pull it out to an explicit temporary. -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
On 16/12/2011 17:57, Ian Kelly wrote: On Fri, Dec 16, 2011 at 10:36 AM, MRABpyt...@mrabarnett.plus.com wrote: On 16/12/2011 16:49, John Gordon wrote: According to the documentation on re.sub(), it replaces the leftmost matching pattern. However, I want to replace the *longest* matching pattern, which is not necessarily the leftmost match. Any suggestions? I'm working with IPv6 CIDR strings, and I want to replace the longest match of (:|$)+ with :. But when I use re.sub() it replaces the leftmost match, even if there is a longer match later in the string. I'm also looking for a regexp that will remove leading zeroes in each four-digit group, but will leave a single zero if the group was all zeroes. How about this: result = re.sub(r\b0+(\d)\b, r\1, string) Close. pattern = r'\b0+([1-9a-f]+|0)\b' re.sub(pattern, r'\1', string, flags=re.IGNORECASE) Ah, OK. The OP said digit instead of hex digit. That's my excuse. :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
Nathan Rice, 16.12.2011 18:48: I realize this has been discussed in the past, I hope that I am presenting a slightly different take on the subject that will prove interesting. This is primarily motivated by my annoyance with using comprehensions in certain circumstances. Currently, if you want to perform successive transformations on the elements of a list, a couple of options: 1. Successive comprehensions: L2 = [X(e) for e in L1] L3 = [Y(e) for e in L2] L4 = [Z(e) for e in L3] or L2 = [e.X() for e in L1] This gets the job done and gives you access to all the intermediate values, but isn't very succinct, particularly if you are in the habit of using informative identifiers. 2. One comprehension: L2 = [Z(X(Y(e))) for e in L1] or L2 = [e.X().Y().Z() for e in L1] This gets the job done, but doesn't give you access to all the intermediate values, and tends to be pretty awful to read. Having typed lists let you take preexisting string/int/etc methods and expose them in a vectorized context and provides an easy way for developers to support both vectors and scalars in a single function (you could easily fix other people's functions dynamically to support both). Additionally, typed lists/iterators will allow improved code analysis and optimization. The PyPy people have already stated that they are working on implementing different strategies for lists composed of a single type, so clearly there is already community movement in this direction. Just compare the above examples to their type-aware counterparts: L2 = X(L1) L2 = L1.X() L2 = Z(Y(X(L1))) L2 = L1.X().Y().Z() What keeps you from implementing this? You don't need to change the language for it, just wrap the list in a class that overrides __getattr__() to return something that does the appropriate transformation for each element. I would be surprised if you needed more than a couple of lines of Python code for that. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
On Sat, Dec 17, 2011 at 5:05 AM, Roy Smith r...@panix.com wrote: Most of this was TL:DNR, but I will admit I often wish for a better way to log intermediate values. For example, a common pattern in the code I'm working with now is functions that end in: return [Foo(x) for x in bunch_of_x_thingies] When something goes amiss and I want to debug the problem, I often transform that into: temp = [Foo(x) for x in bunch_of_x_thingies] logger.debug(temp) return temp It would be convenient to be able to get at and log the intermediate value without having to pull it out to an explicit temporary. tee = lambda func,arg: (func(arg),arg)[1] return tee(logger.debug,[Foo(x) for x in bunch_of_x_thingies]) ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
On 16 December 2011 18:25, Chris Angelico ros...@gmail.com wrote: tee = lambda func,arg: (func(arg),arg)[1] What a strange way to spell it! def tee(func, arg): func(arg) return arg -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
In article jcfsrk$skh$1...@reader1.panix.com, John Gordon gor...@panix.com wrote: I'm working with IPv6 CIDR strings, and I want to replace the longest match of (:|$)+ with :. But when I use re.sub() it replaces the leftmost match, even if there is a longer match later in the string. I'm also looking for a regexp that will remove leading zeroes in each four-digit group, but will leave a single zero if the group was all zeroes. Having done quite a bit of IPv6 work, my opinion here is that you're trying to do The Wrong Thing. What you want is an IPv6 class which represents an address in some canonical form. It would have constructors which accept any of the RFC-2373 defined formats. It would also have string formatting methods to convert the internal form into any of these formats. Then, instead of attempting to regex your way directly from one string representation to another, you would do something like: addr_string = FEDC:BA98:7654:3210:FEDC:BA98:7654:321 print IPv6(addr_string).to_short_form() -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
On Sat, Dec 17, 2011 at 5:38 AM, Arnaud Delobelle arno...@gmail.com wrote: On 16 December 2011 18:25, Chris Angelico ros...@gmail.com wrote: tee = lambda func,arg: (func(arg),arg)[1] What a strange way to spell it! def tee(func, arg): func(arg) return arg I started with that version and moved to the lambda for compactness. But either way works. It's no more strange than the way some people omit the u from colour. :) ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
Nothing stops me from implementing it, in fact it is VERY trivial to wrap member class methods onto a list subclass, and wrap functions to support vectorized behavior. The problem is that as soon as you hit anything outside your code that returns a list or iterator, everything gets blown away unless you explicitly wrap the return value, which entirely defeats the point. On Fri, Dec 16, 2011 at 1:23 PM, Stefan Behnel stefan...@behnel.de wrote: Nathan Rice, 16.12.2011 18:48: I realize this has been discussed in the past, I hope that I am presenting a slightly different take on the subject that will prove interesting. This is primarily motivated by my annoyance with using comprehensions in certain circumstances. Currently, if you want to perform successive transformations on the elements of a list, a couple of options: 1. Successive comprehensions: L2 = [X(e) for e in L1] L3 = [Y(e) for e in L2] L4 = [Z(e) for e in L3] or L2 = [e.X() for e in L1] This gets the job done and gives you access to all the intermediate values, but isn't very succinct, particularly if you are in the habit of using informative identifiers. 2. One comprehension: L2 = [Z(X(Y(e))) for e in L1] or L2 = [e.X().Y().Z() for e in L1] This gets the job done, but doesn't give you access to all the intermediate values, and tends to be pretty awful to read. Having typed lists let you take preexisting string/int/etc methods and expose them in a vectorized context and provides an easy way for developers to support both vectors and scalars in a single function (you could easily fix other people's functions dynamically to support both). Additionally, typed lists/iterators will allow improved code analysis and optimization. The PyPy people have already stated that they are working on implementing different strategies for lists composed of a single type, so clearly there is already community movement in this direction. Just compare the above examples to their type-aware counterparts: L2 = X(L1) L2 = L1.X() L2 = Z(Y(X(L1))) L2 = L1.X().Y().Z() What keeps you from implementing this? You don't need to change the language for it, just wrap the list in a class that overrides __getattr__() to return something that does the appropriate transformation for each element. I would be surprised if you needed more than a couple of lines of Python code for that. Stefan -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
2. One comprehension: L2 = [Z(X(Y(e))) for e in L1] or L2 = [e.X().Y().Z() for e in L1] I want to say that maybe this is better done by functions like map() (although, Python is missing a composition operator which might be handy, and mapping method calls isn't pretty). I don't know that it belongs as a method on lists, especially since that means you can't do the same thing on, for example, generators. Or I guess, the easy answer to that lattermost objection is to make it typed iterators rather than typed lists. -- Devin On Fri, Dec 16, 2011 at 12:48 PM, Nathan Rice nathan.alexander.r...@gmail.com wrote: I realize this has been discussed in the past, I hope that I am presenting a slightly different take on the subject that will prove interesting. This is primarily motivated by my annoyance with using comprehensions in certain circumstances. Currently, if you want to perform successive transformations on the elements of a list, a couple of options: 1. Successive comprehensions: L2 = [X(e) for e in L1] L3 = [Y(e) for e in L2] L4 = [Z(e) for e in L3] or L2 = [e.X() for e in L1] This gets the job done and gives you access to all the intermediate values, but isn't very succinct, particularly if you are in the habit of using informative identifiers. 2. One comprehension: L2 = [Z(X(Y(e))) for e in L1] or L2 = [e.X().Y().Z() for e in L1] This gets the job done, but doesn't give you access to all the intermediate values, and tends to be pretty awful to read. Having typed lists let you take preexisting string/int/etc methods and expose them in a vectorized context and provides an easy way for developers to support both vectors and scalars in a single function (you could easily fix other people's functions dynamically to support both). Additionally, typed lists/iterators will allow improved code analysis and optimization. The PyPy people have already stated that they are working on implementing different strategies for lists composed of a single type, so clearly there is already community movement in this direction. Just compare the above examples to their type-aware counterparts: L2 = X(L1) L2 = L1.X() L2 = Z(Y(X(L1))) L2 = L1.X().Y().Z() Also, this would provide a way to clean up stuff like: \n.join(l.capitalize() for l in my_string.split(\n)) into: my_string.split(\n).capitalize().join_this(\n) Before anyone gets up in arms at the idea of statically typed python, what I am suggesting here would be looser than that. Basically, I believe it would be a good idea in instances where it is known that a list of single type is going to be returned, to return a list subclass (for example, StringList, IntegerList, etc). To avoid handcuffing people with types, the standard list modification methods could be hooked so that if an object of an incorrect type is placed in the list, a warning is raised and the list converts to a generic object list. The only stumbling block is that you can't use __class__ to convert from stack types to heap types in CPython. My workaround for this would be to have a factory that creates generic List classes, modifying the bases to produce the correct behavior. Then, converting from a typed list to a generic object list would just be a matter of removing a member from the bases for a class. This of course basically kills the ability to perform type specific list optimization in CPython, but that isn't necessarily true for other implementations. The additional type information would be preserved for code analysis in any case. The case would be even simpler for generators and other iterators, as you don't have to worry about mutation. I'd like to hear people's thoughts on the subject. Currently we are throwing away useful information in many cases that could be used for code analysis, optimization and simpler interfaces. I believe that typed lists that get demoted to normal lists with a warning on out of type operations preserve this information while providing complete backwards compatibility and freedom. Nathan -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
On 16 dec, 18:38, rusi rustompm...@gmail.com wrote: On Dec 16, 3:25 pm, Eelco hoogendoorn.ee...@gmail.com wrote: Pseudo-backwards compatibility with other languages, I couldnt not care less for. Double negations n Goedelian situations have interesting implications (tho here its triple) Heh. Well at least my extra (unintended) negation is semantically consistent with the actual english usage of the phrase, which omits the negation completely :). (I could care less) But ill stick with trying to change one language at a time :). -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
Chris Angelico wrote: It's no more strange than the way some people omit the u from colour. :) Bonum Petronio Arbiteri, bonum mihi. Mel. -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
Nathan Rice, 16.12.2011 19:51: Nothing stops me from implementing it, in fact it is VERY trivial to wrap member class methods onto a list subclass, and wrap functions to support vectorized behavior. The problem is that as soon as you hit anything outside your code that returns a list or iterator, everything gets blown away unless you explicitly wrap the return value, which entirely defeats the point. The point you are trying to make, maybe. Stefan PS: note that you top-posted in your reply, you should try to avoid that. -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
Roy Smith r...@panix.com writes: When something goes amiss and I want to debug the problem, I often transform that into: temp = [Foo(x) for x in bunch_of_x_thingies] logger.debug(temp) return temp It would be convenient to be able to get at and log the intermediate value without having to pull it out to an explicit temporary. What's wrong with that though? You're not “pulling it out to” anything; you're binding a name to the value in order to do several things with it. Exactly what you say you want to do. It's explicit and clear. -- \ “What we usually pray to God is not that His will be done, but | `\ that He approve ours.” —Helga Bergold Gross | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: Make a small function thread safe
On 17 December 2011 02:05, Brad Tilley kj4...@gmail.com wrote: On Dec 16, 9:36 am, Tim Wintle tim.win...@teamrubber.com wrote: should be: def run(t): with lock: shared_container.append(t.name) (or lock.acquire() and lock.release() as you mentioned) Thanks Tim. The with statement is closer to the C++ code (IMO) more so than the explicit acquire() and release() so I'll use that approach. I appreciate your advice. Most definitely. The acquire/release code shown was erroneous, since it would not release if an exception was thrown. The with code is effectively equivalent to: lock.acquire() try: ... finally: lock.release() Tim Delaney -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
In mailman.3737.1324054637.27778.python-l...@python.org Devin Jeanpierre
jeanpierr...@gmail.com writes:
You could use re.finditer to find the longest match, and then replace
it manually by hand (via string slicing).
(a match is the longest if (m.end() - m.start()) is the largest --
so, max(re.finditer(...), key=3Dlambda m: (m.end() =3D m.start()))
I ended up doing something similar:
# find the longest match
longest_match = ''
for word in re.findall('((:?)+)', ip6):
if len(word[0]) len(longest_match):
longest_match = word[0]
# if we found a match, replace it with a colon
if longest_match:
ip6 = re.sub(longest_match, ':', ip6, 1)
Thanks!
--
John Gordon A is for Amy, who fell down the stairs
gor...@panix.com B is for Basil, assaulted by bears
-- Edward Gorey, The Gashlycrumb Tinies
--
http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
In mailman.3742.1324058429.27778.python-l...@python.org Ian Kelly
ian.g.ke...@gmail.com writes:
I'm also looking for a regexp that will remove leading zeroes in each
four-digit group, but will leave a single zero if the group was all
zeroes.
pattern = r'\b0{1,3}([1-9a-f][0-9a-f]*|0)\b'
re.sub(pattern, r'\1', string, flags=re.IGNORECASE)
Perfect. Thanks Ian!
--
John Gordon A is for Amy, who fell down the stairs
gor...@panix.com B is for Basil, assaulted by bears
-- Edward Gorey, The Gashlycrumb Tinies
--
http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
In roy-7c4e8a.13361716122...@news.panix.com Roy Smith r...@panix.com writes: Having done quite a bit of IPv6 work, my opinion here is that you're trying to do The Wrong Thing. What you want is an IPv6 class which represents an address in some canonical form. It would have constructors which accept any of the RFC-2373 defined formats. It would also have string formatting methods to convert the internal form into any of these formats. Then, instead of attempting to regex your way directly from one string representation to another, you would do something like: addr_string = FEDC:BA98:7654:3210:FEDC:BA98:7654:321 print IPv6(addr_string).to_short_form() This does sound like a more robust solution. I'll give it some thought. Thanks Roy! -- John Gordon A is for Amy, who fell down the stairs gor...@panix.com B is for Basil, assaulted by bears -- Edward Gorey, The Gashlycrumb Tinies -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
On 16/12/2011 21:04, John Gordon wrote:
Inmailman.3737.1324054637.27778.python-l...@python.org Devin
Jeanpierrejeanpierr...@gmail.com writes:
You could use re.finditer to find the longest match, and then replace
it manually by hand (via string slicing).
(a match is the longest if (m.end() - m.start()) is the largest --
so, max(re.finditer(...), key=3Dlambda m: (m.end() =3D m.start()))
I ended up doing something similar:
# find the longest match
longest_match = ''
for word in re.findall('((:?)+)', ip6):
if len(word[0]) len(longest_match):
longest_match = word[0]
# if we found a match, replace it with a colon
if longest_match:
ip6 = re.sub(longest_match, ':', ip6, 1)
For a simple replace, using re is probably overkill. The .replace
method is a better solution:
ip6 = longest_match.replace(ip6, ':', 1)
--
http://mail.python.org/mailman/listinfo/python-list
Re: AttributeError in with statement (3.2.2)
On 12/16/2011 4:22 AM, Steven D'Aprano wrote: On Thu, 15 Dec 2011 19:39:17 -0500, Terry Reedy wrote: [...] After reading your post, I think I have worked out where our disagreement lines: you think that bound methods and instance methods are not the same thing, Do you agree that an unbound method and a bound method are different? In Python, as indicated by the glossary entry, an unspecified 'method' is usually meant to be an unbound method. It is am important distinction and I do not see why you insist on confusing the two. and that a function defined inside a class is different from a function outside of a class. That, and your repetition of the same claim further on, is a insulting lie. Def statements always create functions. I have known that for 14 years since the first day I started with Python. I have never thought differently. If you actually think that I have, you are wrong. What I have said from my first response is that a function that is an attribute of a class, *whether defined in or outside the class*, gets special treatment when accessed via an instance of the class. And that is the truth. If you are ever interested in learning anything from me on this subject, re=read what I already wrote with a more open mind than you have so far. Otherwise, I am done. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: Make a small function thread safe
On 12/17/2011 01:30 AM, Brad Tilley wrote: Or perhaps run should look like this instead: def run(t): lock.acquire() shared_container.append(t.name http://t.name) lock.release() That seems a bit barbaric to me, not sure. change that to: def run(t): with lock: shared_container.append(t.name http://t.name) the `with-statement` will call lock.acquire() and lock.release(). -- http://mail.python.org/mailman/listinfo/python-list
Re: Making the case for typed lists/iterators in python
On 12/16/2011 1:05 PM, Roy Smith wrote: I'm working with now is functions that end in: return [Foo(x) for x in bunch_of_x_thingies] When something goes amiss and I want to debug the problem, I often transform that into: temp = [Foo(x) for x in bunch_of_x_thingies] logger.debug(temp) return temp It would be convenient to be able to get at and log the intermediate value without having to pull it out to an explicit temporary. Decorate the function with @logreturn and you do not have to touch the function code. If the logging module does not now have such a decorator predefined (I simply do not know), perhaps it should. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: re.sub(): replace longest match instead of leftmost match?
On 12/16/2011 1:36 PM, Roy Smith wrote: What you want is an IPv6 class which represents an address in some canonical form. It would have constructors which accept any of the RFC-2373 defined formats. It would also have string formatting methods to convert the internal form into any of these formats. Then, instead of attempting to regex your way directly from one string representation to another, you would do something like: addr_string = FEDC:BA98:7654:3210:FEDC:BA98:7654:321 print IPv6(addr_string).to_short_form() There are at least 2 third-party IP classes in use. I would not be surprised if at least one of them does this. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Interpreter Error with PyDev (Eclipse IDE)
Thanks Fabio! I looked at my environment variables, and the only one python related was PYTHONHOME, and that was set to C:\csvn\Python25. So I changed that to C:\Python32\ and I added an environment variable for PYTHONROOT and set that to the same value. It now seems to work! I must have had a some python directories laying around from an odd svn installation or something... Thanks again! From: Fabio Zadrozny fabi...@gmail.com To: Joshua Jodrey jdjod...@yahoo.com Cc: python-list@python.org python-list@python.org Sent: Friday, December 16, 2011 12:57 PM Subject: Re: Python Interpreter Error with PyDev (Eclipse IDE) It seems you have a version of Python 2.5 in your system and when starting up Python 3.2.2 it's getting things from 2.5 (this would probably also happen on the command line). The usual suspect is that you defined a PYTHONROOT variable which is pointing to Python 2.5 and not to the python you're using... Cheers, Fabio On Thu, Dec 15, 2011 at 10:20 PM, Joshua Jodrey jdjod...@yahoo.com wrote: Hi, This is my first email to this list, so I apologize if there's a better mailing-list for this type of question. I'm looking to get started with python development, so I downloaded Python 3.2.2 and PyDev IDE for Eclipse. When I go to configure my interpreter for a new python project, Windows gives me the following error: python.exe has stopped working and then Eclipse shows Error getting info on interpreter See error log for details. No output was in the standard output when trying to create the interpreter info. The error output contains:Fatal Python error: Py_Initialize: unable to load the file system codec File C:\csvn\Python25\\lib\encodings\__init__.py, line 120 raise CodecRegistryError,\ ^ SyntaxError: invalid syntax This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Does anybody have any idea what this means or what I'm doing wrong? I've tried re-installing Python, but still can't get it to work. And again, if I'm in the wrong place, please direct me to the proper mailing-list or forum. Thanks! Josh P.S. I'm not subscribed to this mailer, so please include me in your replies! -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
Eelco wrote: the actual english usage of the phrase, which omits the negation completely :). (I could care less) No, that's the American usage. The English usage is I couldn't care less, which has the advantage of actually making sense. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: AttributeError in with statement (3.2.2)
Terry Reedy wrote: On 12/16/2011 4:22 AM, Steven D'Aprano wrote: On Thu, 15 Dec 2011 19:39:17 -0500, Terry Reedy wrote: [...] After reading your post, I think I have worked out where our disagreement lies: you think that bound methods and instance methods are not the same thing, Do you agree that an unbound method and a bound method are different? In Python, as indicated by the glossary entry, an unspecified 'method' is usually meant to be an unbound method. I think you two are in violent agreement as far as how Python is functioning, and the conflict is in the names given to the various pieces... I think a glossary would help (please correct me): function: callable code suite method: function that lives in a class unbound method: function that lives in a class bound method: callable wrapper around function that has been extracted from class that will supply the instance object to the function (note: Python does not save these, they are recreated at each lookup) and here is where I think you two diverge: instance method (Steven): a bound method that has been saved into the instance __dict__ (no matter how created) instance method (Terry): a function that must be looked up in the class Have I missed anything? Honestly-trying-learn-the-distinctions-ly yours, ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
On Dec 17, 12:49 am, Gregory Ewing greg.ew...@canterbury.ac.nz wrote: Eelco wrote: the actual english usage of the phrase, which omits the negation completely :). (I could care less) No, that's the American usage. The English usage is I couldn't care less, which has the advantage of actually making sense. -- Greg Oh thanks for clearing that up, never noticed a division along these lines. And yes, I agree; 'I couldnt care less' makes much more sense. 'I could care less' can only make sense if you interpret it sarcastically, as if omitting an 'oh wait, I cant', but that does not seem congruent with how its typically pronounced. Just another case of suboptimal language design; but where can you submit EEP's? -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
In article 2420abd7-7d91-4bc9-bb3b-d8ec1680e...@u32g2000yqe.googlegroups.com, Eelco hoogendoorn.ee...@gmail.com wrote: And yes, I agree; 'I couldnt care less' makes much more sense. 'I could care less' can only make sense if you interpret it sarcastically, as if omitting an 'oh wait, I cant', but that does not seem congruent with how its typically pronounced. I care so little about the subject that I am unwilling to spend one of my precious apostrophes to properly express the sentiment -- http://mail.python.org/mailman/listinfo/python-list
Re: AttributeError in with statement (3.2.2)
Ethan Furman wrote: Terry Reedy wrote: On 12/16/2011 4:22 AM, Steven D'Aprano wrote: On Thu, 15 Dec 2011 19:39:17 -0500, Terry Reedy wrote: [...] After reading your post, I think I have worked out where our disagreement lies: you think that bound methods and instance methods are not the same thing, Do you agree that an unbound method and a bound method are different? In Python, as indicated by the glossary entry, an unspecified 'method' is usually meant to be an unbound method. I think you two are in violent agreement as far as how Python is functioning, and the conflict is in the names given to the various pieces... I think a glossary would help (please correct me): function: callable code suite method: function that lives in a class unbound method: function that lives in a class bound method: callable wrapper around function that has been extracted from class that will supply the instance object to the function (note: Python does not save these, they are recreated at each lookup) I think the above 'bound method' definition should be attributed to Terry, and Steven's follows: bound method: callable wrapper around any function that will accept an instance object as the first parameter, and the wrapper will supply said instance object when calling the function (and where/how function was created is irrelevent, as is where the wrapper is stored) and here is where I think you two diverge: instance method (Steven): a bound method that has been saved into the instance __dict__ (no matter how created) instance method (Terry): a function that must be looked up in the class Have I missed anything? Honestly-trying-learn-the-distinctions-ly yours, ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
On Fri, 16 Dec 2011 11:40:11 -0800, Eelco wrote: On 16 dec, 18:38, rusi rustompm...@gmail.com wrote: On Dec 16, 3:25 pm, Eelco hoogendoorn.ee...@gmail.com wrote: Pseudo-backwards compatibility with other languages, I couldnt not care less for. Double negations n Goedelian situations have interesting implications (tho here its triple) Heh. Well at least my extra (unintended) negation is semantically consistent with the actual english usage of the phrase, which omits the negation completely :). (I could care less) Oh please. I could care less is not English. That's American. Here in Australia, we follow the English practice of saying that we couldn't care less. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: AttributeError in with statement (3.2.2)
On Fri, 16 Dec 2011 17:05:57 -0500, Terry Reedy wrote: On 12/16/2011 4:22 AM, Steven D'Aprano wrote: On Thu, 15 Dec 2011 19:39:17 -0500, Terry Reedy wrote: [...] After reading your post, I think I have worked out where our disagreement lines: you think that bound methods and instance methods are not the same thing, Do you agree that an unbound method and a bound method are different? Are different or are different types? Bound and unbound methods in Python 2 are the same type. They are different in the sense that one is effectively a curry of the other, but they are implemented as a single type. So presumably the difference is a bound method has a slot filled and an unbound method doesn't, or some other implementation detail. In Python 3, unbound methods don't exist. In Python, as indicated by the glossary entry, an unspecified 'method' is usually meant to be an unbound method. I think you are badly confused here. The glossary talks about calling methods as an attribute of an instance, e.g. instance.method(), and the method receiving the instance as the first argument. That's a bound method, not unbound. How do you conclude that this indicates that an unspecified method is unbound? Your conclusion is especially nonsensical because unbound methods don't exist in Python 3 -- you're alleging that the usual meaning of method is something which no longer exists in the language! method A function which is defined inside a class body. If called as an attribute of an instance of that class, the method will get the instance object as its first argument (which is usually called self). See function and nested scope. http://docs.python.org/glossary.html It is am important distinction and I do not see why you insist on confusing the two. It is not an important distinction, and I am not confusing the two. Bound or unbound, it is still an instance method. and that a function defined inside a class is different from a function outside of a class. That, and your repetition of the same claim further on, is a insulting lie. If you can't assume I'm carrying on this discussion in good faith, then we have a serious problem. This is not like you Terry -- I've been reading your posts for many years, and you're not usually so obstreperous. Def statements always create functions. I have known that for 14 years since the first day I started with Python. I have never thought differently. If you actually think that I have, you are wrong. I'm glad to hear it. But nevertheless you have made statements (which I quoted, and you deleted from your reply) that suggest the opposite. If I have misinterpreted them, or if you had worded them badly, there's no need to attribute malice to me. Calling me a liar for something said in good faith and which I prefixed with I think is simply not cool. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: % is not an operator [was Re: Verbose and flexible args and kwargs syntax]
On Fri, Dec 16, 2011 at 7:54 PM, Steven D'Aprano steve+comp.lang.pyt...@pearwood.info wrote: On Fri, 16 Dec 2011 11:40:11 -0800, Eelco wrote: On 16 dec, 18:38, rusi rustompm...@gmail.com wrote: On Dec 16, 3:25 pm, Eelco hoogendoorn.ee...@gmail.com wrote: Pseudo-backwards compatibility with other languages, I couldnt not care less for. Double negations n Goedelian situations have interesting implications (tho here its triple) Heh. Well at least my extra (unintended) negation is semantically consistent with the actual english usage of the phrase, which omits the negation completely :). (I could care less) Oh please. I could care less is not English. That's American. Here in Australia, we follow the English practice of saying that we couldn't care less. Well the phrase is still somewhat controversial in the US. I never heard it until age 19 (in 1966) and have always been somewhat disdainful of those using it. But it appears to be hopeless. http://articles.boston.com/2010-10-24/lifestyle/29303907_1_care-peeves-decades -- http://mail.python.org/mailman/listinfo/python-list
Re: Make a small function thread safe
On 12/16/2011 2:08 PM, Lie Ryan wrote: On 12/17/2011 01:30 AM, Brad Tilley wrote: Or perhaps run should look like this instead: def run(t): lock.acquire() shared_container.append(t.name http://t.name) lock.release() That seems a bit barbaric to me, not sure. change that to: def run(t): with lock: shared_container.append(t.name http://t.name) the `with-statement` will call lock.acquire() and lock.release(). And, importantly, if you leave the with via an exception, the lock will be unlocked. John Nagle -- http://mail.python.org/mailman/listinfo/python-list
root[:]=[root,root]
Hi,all. Could anybody tell how this code works? root = [None, None] root[:] = [root, root] root [[...], [...]] root[0] [[...], [...]] root[0][0][1][1][0][0][0][1][1] [[...], [...]] Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: AttributeError in with statement (3.2.2)
On Fri, 16 Dec 2011 15:26:30 -0800, Ethan Furman wrote: Terry Reedy wrote: On 12/16/2011 4:22 AM, Steven D'Aprano wrote: [...] I think you two are in violent agreement as far as how Python is functioning, and the conflict is in the names given to the various pieces... I think a glossary would help (please correct me): function: callable code suite Sure, why not? Informally: a function is some object which can be called and returns a result. Hence we sometimes call str() and int() functions even though they are actually implemented as types. Callable would be better for such informal use, but newbies may not recognise the term. To be more precise: a function is a particular type of callable object created by the def and lambda statements. method: function that lives in a class Informally, I'm happy with that definition, and use it myself. Under 99% of circumstances, it would be overly pedantic to describe spam in the following as anything other than a method: class C: def spam(self): pass Call it the duck-type principle: since spam quacks like a duck, we might as well call it a duck. If you only care about the easy cases, then spam is a method and we're done. But as a formal definition, it fails on two fronts: functions that live inside classes are not actually methods, they are functions, and while methods are commonly found in classes, they can also be found in instances, or anywhere else for that matter. Functions inside classes are still functions I said that since spam quacks like a method, we might as well call it a method. But it doesn't swim like a method: it's actually still a function with a remarkable power of mimicry. There are places and times where the fact that spam is not actually a method comes through. The three most important examples in my opinion are: * inside the class suite, during class definition time, if you use or inspect spam, you will see it is a function and not a method; * if you bypass the getattr mechanism for looking up attributes, e.g. use C.__dict__['spam'] instead of C().spam, you will see that spam is stored in the dict as a function object, not a method object; * (Python 3 only) if use the standard getattr mechanism, but call it on the class instead of an instance, you will get the function object instead of a method. So, to be precise: spam is actually a function. It is stored as a function inside C.__dict__, but when you retrieve it using C().spam Python automagically builds a method object wrapping spam and gives you that instead. This distinction is important, well, hardly ever, but on the rare occasion it is important, you need to know it. One example of when it may be important: because methods are created as needed, you can't assume that identity checks will necessarily pass for methods: `inst.spam is inst.spam` may not be true. Methods can be created outside of classes - The normal way to get a method is by defining it inside a class. In Java, I believe that is the *only* way to get methods, but this is Python, and we have other options. Methods are first class objects, which means they have a type and a constructor, so if you can get hold of their type, you can make them by hand. You can retrieve the method type two ways: * call type on a method you made the usual way: type(C().spam); * or import types and use types.MethodType. Confusingly, the method type calls itself instancemethod but is exported via the types module as MethodType. Oh well. MethodType requires two arguments, In Python 2, it accepts an optional third argument. Since Python 2 is the past, I'll only talk about the Python 3 version, where the signature might look something like this: MethodType(callable, instance) = instancemethod object This creates a wrapper around callable (usually, but not necessarily a function) and binds instance to that wrapper so the first argument (conventionally called self) can be automatically provided. Another way to create methods is by calling the function object __get__ method by hand. That's what gets used in the normal C().spam case. So you can create methods without putting them inside a class. One trick is that you can customise behaviour on a per-instance basis by overriding the normal method living inside the class with one which lives inside the instance: class C: def spam(self): return Spam spam spam, lovely SPAM!!! c = C() c.spam = types.MethodType(lambda self: Bloody vikings!, c) Instance c now has a custom method which overrides C.spam. [Aside #1: I think this was the original point of contention between Terry and I. For reasons I still don't understand, it seems to me that he denies that the per-instance method spam is actually a method, since it doesn't live inside the class.] [Aside #2: this per-instance method trick may not work for
Re: root[:]=[root,root]
On 12/17/2011 01:40 PM, YAN HUA wrote: Hi,all. Could anybody tell how this code works? root = [None, None] First, you're creating a list of two None, let's say it's list-1. Then you bind the name 'root' to list-1. root[:] = [root, root] Next, you assign list-1's first member with list-1 and list-1's second member with list-1. root [[...], [...]] The result is a recursive list, both list-1's first and second member is list-1 itself. root[0] [[...], [...]] root[0][0][1][1][0][0][0][1][1] [[...], [...]] Thanks. -- http://mail.python.org/mailman/listinfo/python-list
[issue13609] Add os.get_terminal_size() function
Zbyszek Szmek zbys...@in.waw.pl added the comment: The patch is already almost there (in #13041). I'll post an updated version here in a moment. -- nosy: +zbysz ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue13609 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue13611] Integrate ElementC14N module into xml.etree package
New submission from Stefan Behnel sco...@users.sourceforge.net: The ElementC14N.py module by Fredrik Lundh implements XML canonicalisation for the ElementTree serialiser. Given that the required API hooks to use it are already in xml.etree.ElementTree, this would make a nice, simple and straight forward addition to the existing xml.etree package. The source can be found here (unchanged since at least 2009): https://bitbucket.org/effbot/et-2009-provolone/src/tip/elementtree/elementtree/ElementC14N.py Note that the source needs some minor modifications to use relative imports at the top. Also, the 2.3 compatibility code section can be dropped. -- components: Library (Lib), XML messages: 149598 nosy: scoder priority: normal severity: normal status: open title: Integrate ElementC14N module into xml.etree package type: enhancement versions: Python 3.3 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue13611 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue13611] Integrate ElementC14N module into xml.etree package
Changes by Antoine Pitrou pit...@free.fr: -- nosy: +flox ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue13611 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue11900] 2.7.1 unicode subclasses not calling __str__() for print statement
Amaury Forgeot d'Arc amaur...@gmail.com added the comment: However, it is a real change from 2.6 to 2.7 that breaks code. John, this issue is not the same as the one above. The difference between Python 2.6 and Python 2.7.2 you mention only applies to % formatting. The change is clearly documented in http://docs.python.org/dev/whatsnew/2.7.html It’s now possible for a subclass of the built-in unicode type to override the __unicode__() method. This is clearly a bug in the application. There are many ways to break compatibility with bogus code... -- nosy: +amaury.forgeotdarc ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue11900 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7652] Merge C version of decimal into py3k.
Stefan Krah stefan-use...@bytereef.org added the comment: For my part, a two-lines description of the purpose of file is enough. OK, I'll go for small comments in the files themselves and put big ones in separate files. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7652 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6715] xz compressor support
Antoine Pitrou pit...@free.fr added the comment: Is there any reason why this issue is still open? -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6715 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue13612] xml.etree.ElementTree says unknown encoding of a regular encoding
New submission from Dongying Zhang zhangdongying1...@gmail.com: I've been trying to parse xml string using python, codes following: #-*- coding: utf-8 -*- import xml.etree.ElementTree as xmlet s = '?xml version=1.0 encoding=GBK?info/info' xmlet.fromstring(s) Then: $ python2.6 test.py or: $ pypy test.py Traceback message came out like this: Traceback (most recent call last): File test.py, line 4, in module xmlet.fromstring(s) File /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/xml/etree/ElementTree.py, line 963, in XML parser.feed(text) File /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/xml/etree/ElementTree.py, line 1245, in feed self._parser.Parse(data, 0) xml.parsers.expat.ExpatError: unknown encoding: line 1, column 30 I've seen this in following cases: Python2.5.6 on Mac OS X Lion Python2.6.5 on Ubuntu 10.04 pypy1.7.0 on Mac OS X Lion But not in these cases: Python2.6.7 on Mac OS X Lion Python2.7.1 on Mac OS X Lion -- components: Library (Lib) files: test.py messages: 149602 nosy: dongying priority: normal severity: normal status: open title: xml.etree.ElementTree says unknown encoding of a regular encoding versions: Python 2.6 Added file: http://bugs.python.org/file23974/test.py ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue13612 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue13612] xml.etree.ElementTree says unknown encoding of a regular encoding
Changes by Dongying Zhang zhangdongying1...@gmail.com: -- versions: +3rd party ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue13612 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue13612] xml.etree.ElementTree says unknown encoding of a regular encoding
Changes by Dongying Zhang zhangdongying1...@gmail.com: -- type: - behavior ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue13612 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1559549] ImportError needs attributes for module and file name
Antoine Pitrou pit...@free.fr added the comment: fullname is technically wrong: import logging.bar Traceback (most recent call last): File stdin, line 1, in module ImportError: No module named 'bar' module_name sounds fine and explicit enough to me. Also, as Eric points out, there are many places where an ImportError is raised. You might want to create a private helper API. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1559549 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue11379] Remove lightweight from minidom description
Stefan Behnel sco...@users.sourceforge.net added the comment: I started a mailing list thread on the same topic: http://thread.gmane.org/gmane.comp.python.devel/127963 Especially see http://thread.gmane.org/gmane.comp.python.devel/127963/focus=128162 where I extract a proposal from the discussion. Basically, there should be a note at the top of the xml.dom documentation as follows: [[Note: The xml.dom.minidom module provides an implementation of the W3C-DOM whose API is similar to that in other programming languages. Users who are unfamiliar with the W3C-DOM interface or who would like to write less code for processing XML files should consider using the xml.etree.ElementTree module instead.]] I think this should go on the xml.dom.minidom page as well as the xml.dom package page. Hand-wavingly, users who are new to the DOM are more likely to hit the package page first, whereas those who know it already will likely find the MiniDOM page directly. Note that I'd still encourage the removal of the misleading word lightweight until it makes sense to put it back in a meaningful way. I therefore propose the following minimalistic changes to the first paragraph on the minidom page: xml.dom.minidom is a [-XXX: light-weight] implementation of the Document Object Model interface. It is intended to be simpler than the full DOM and also [+XXX: provide a] significantly smaller [+XXX: API]. Additionally, the documentation on the xml.sax page would benefit from the following paragraph: [[Note: The xml.sax package provides an implementation of the SAX interface whose API is similar to that in other programming languages. Users who are unfamiliar with the SAX interface or who would like to write less code for efficient stream processing of XML files should consider using the iterparse() function in the xml.etree.ElementTree module instead.]] -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue11379 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6715] xz compressor support
Nadeem Vawda nadeem.va...@gmail.com added the comment: Yes, almost half of the buildbots still don't have the xz-utils headers installed, and thus are not building/testing the lzma module. I've kept the issue open as a reminder to myself to follow up on this. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6715 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1785] inspect gets broken by some descriptors
Antoine Pitrou pit...@free.fr added the comment: Updated patch for 3.2. -- stage: - patch review versions: +Python 3.2 -Python 2.6 Added file: http://bugs.python.org/file23975/inspect-and-pydoc-bug2.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1785 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1785] inspect gets broken by some descriptors
Antoine Pitrou pit...@free.fr added the comment: Updated patch that adds a test for classifying builtin types (checks that ``inspect.classify_class_attrs(type)`` does not throw as in issue13581). -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1785 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1785] inspect gets broken by some descriptors
Changes by Antoine Pitrou pit...@free.fr: Added file: http://bugs.python.org/file23976/inspect-and-pydoc-bug3.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1785 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12809] Missing new setsockopts in Linux (eg: IP_TRANSPARENT)
Changes by Antoine Pitrou pit...@free.fr: -- nosy: +neologix ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12809 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue13610] On Python parsing numbers.
Charles-François Natali neolo...@free.fr added the comment:
Can this be fixed?
More or less.
The following patch does the trick, but is not really elegant:
--- a/Parser/tokenizer.c2011-06-01 02:39:38.0 +
+++ b/Parser/tokenizer.c2011-12-16 08:48:45.0 +
@@ -1574,6 +1576,10 @@
}
}
tok_backup(tok, c);
+if (is_potential_identifier_start(c)) {
+tok-done = E_TOKEN;
+return ERRORTOKEN;
+}
*p_start = tok-start;
*p_end = tok-cur;
return NUMBER;
python -c 1and 0
File string, line 1
1and 0
^
SyntaxError: invalid token
Note that there are other - although less bothering - limitations:
python -c 1 and@ 2
File string, line 1
1 and@ 2
^
SyntaxError: invalid syntax
This should be catched by the lexer, not the parser (i.e. it should raise an
Invalid token error).
That's a limitation of the ad-hoc scanner.
--
nosy: +neologix
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[issue6695] PyXXX_ClearFreeList for dict, set, and list
Roundup Robot devn...@psf.upfronthosting.co.za added the comment: New changeset 57f0af61da53 by Antoine Pitrou in branch 'default': Issue #6695: Full garbage collection runs now clear the freelist of set objects. http://hg.python.org/cpython/rev/57f0af61da53 -- nosy: +python-dev ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6695 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6695] PyXXX_ClearFreeList for dict, set, and list
Antoine Pitrou pit...@free.fr added the comment: The clearing the dict and list freelists has been added independently, so I committed the part of the patch pertaining to sets. Thank you! -- resolution: - fixed stage: - committed/rejected status: open - closed versions: +Python 3.3 -Python 3.2 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6695 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue11379] Remove lightweight from minidom description
Ezio Melotti ezio.melo...@gmail.com added the comment: xml.dom.minidom is a [-XXX: light-weight] implementation of the Document Object Model interface. This is ok. It is intended to be simpler than the full DOM and also [+XXX: provide a] significantly smaller [+XXX: API]. Doesn't simpler here refer to the API already? Another option is to add somewhere a section like: If you have to work with XML, ElementTree is usually the best choice, because it has a simple API and it's efficient [or whatever]. xml.dom.minidom provides a subset of the W3C-DOM API, and xml.sax a SAX interface., possibly expanding a bit on the differences and showing a minimal example with the 3 different implementations, and then link to it from the other modules' pages. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue11379 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue5424] Packed IPaddr conversion tests should be extended
Changes by Antoine Pitrou pit...@free.fr: -- nosy: +neologix ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue5424 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue13612] xml.etree.ElementTree says unknown encoding of a regular encoding
Amaury Forgeot d'Arc amaur...@gmail.com added the comment: Actually, this fails on 2.6 and 2.7 on wide unicode builds, and passes with narrow unicode builds (on my 64bit Linux box). In pyexpat.c, PyUnknownEncodingHandler accesses 256 characters of a unicode buffer, without checking its length... which happens to be 192 chars long. So buffers overflow, etc. The function has a comment supports only 8bit encodings; indeed. Versions 3.2 and 3.3 happen to pass the test, probably by pure luck. Supporting multibytes codecs won't be easy: pyexpat requires to fill an array which specifies the number of bytes needed by each start byte (for example, in utf-8, 0xc3 starts a 2-bytes sequence, 0xef starts a 3-bytes sequence). Our codecs framwork does not provide this information, and some codecs (gb18030 for example) need the second char to determine whether it will need 4 bytes. -- nosy: +amaury.forgeotdarc ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue13612 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue13609] Add os.get_terminal_size() function
Denilson Figueiredo de Sá denilso...@gmail.com added the comment: Zbyszek, I just looked at [1] and I disagree that the environment variable should have higher precedence. In fact, I believe it should have lower precedence, and should be used as a fallback. [1]: http://bugs.python.org/file23241/patch1.1.diff Reason? Imagine a program is launched, and thus it has COLUMNS set to some value. While the program is running, the user resizes the terminal. I believe (though I have not tested) that the envvar will keep the old value, and this function would return wrong dimensions. In my opinion, the system-specific code (termios/windll) should be tried first, and then the envvars (as fallback). If all else fails, maybe it would be better to return (None, None) and let the caller of this function handle that. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue13609 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10350] errno is read too late
Roundup Robot devn...@psf.upfronthosting.co.za added the comment: New changeset 6a966179c73a by Antoine Pitrou in branch '3.2': Issue #10350: Read and save errno before calling a function which might overwrite it. http://hg.python.org/cpython/rev/6a966179c73a New changeset 8e0b2e75ca7a by Antoine Pitrou in branch 'default': Issue #10350: Read and save errno before calling a function which might overwrite it. http://hg.python.org/cpython/rev/8e0b2e75ca7a -- nosy: +python-dev ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10350 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10350] errno is read too late
Antoine Pitrou pit...@free.fr added the comment: Committed in 3.x. I won't bother backporting to 2.x. Thank you! -- resolution: - fixed stage: patch review - committed/rejected status: open - closed versions: +Python 3.3 -Python 2.7, Python 3.1 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10350 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue9975] Incorrect use of flowinfo and scope_id in IPv6 sockaddr tuple
Changes by Antoine Pitrou pit...@free.fr: -- nosy: +neologix ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue9975 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
