🌐 Mailman 3 July 2008 - Python-list - python.org

Pydev configuration
by Sébastien Boisgérault May 10, 2012

May 10, 2012

Hi, Did anyone managed to change the code font family/size in Pydev (Python Editor Plugin for Eclipse) ? I found how to change the color mapping (Windows/Preference/Pydev) but did not found the font setting. Cheers, SB

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Is there *any* real documentation to PyWin32?
by Benoit April 20, 2012

April 20, 2012

I understand that the Win32 has been said to be itself poorly documented, so perhaps that the documentation that comes with the modules is of similar quality is no coincidence. Maybe I'm still too young in my programming to grasp the good of that documentation, but for myself, it tells me next to nothing. Could anyone point me to anything which may exist that does a better job of explaining the extensions' use? I tried to take a look @ Microsoft's documentation, but it was confusing.

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A 'Python like' language
by Peter Hickman March 3, 2012

March 3, 2012

Well after all this discussion it would appear that a 'Python like' language has appeared => Prothon. http://www.prothon.org/index.html Very alpha, sort of like Python (if you consider the indenting is what makes Python unique) and sort of Ruby in its use of prefixes to define scoping etc (although there is no reference to this trait being borrowed from Ruby). It also quotes Self as being an influence.

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AIX installation can't find zlib
by Larry Whitley Nov. 3, 2011

Nov. 3, 2011

I've just installed the 1.5.2 source distribution on an AIX system and when I say "import zlib" it responds: >>> import zlib Traceback (innermost last): File "<stdin>", line 1, in ? ImportError: No module named zlib >>> I'm not sure where zlib is supposed to be. It's not in the Lib subdirectory of Python-1.5.2. In the Modules subdirectory I find zlibmodule.c. Nothing germaine in the Objects subdirectory. Looked at config.log and config.status, no mention of zlib. Looking at the sys.path I see: .../ldw/Python-1.5.2> python Python 1.5.2 (#1, Jul 26 2000, 14:21:56) [C] on aix4 Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam >>> import sys >>> sys.path ['', '/.../rchland.ibm.com/fs/u1/ldw/Projects/Programs/wtCache', '/.../rchland.ibm.com/fs/u1/ldw/Python-1.5.2/Lib/', '/.../rchland.ibm.com/fs/u1/ldw/Python-1.5.2/Lib/plat-aix4', '/.../rchland.ibm.com/fs/u1/ldw/Python-1.5.2/Lib/lib-tk', '/.../rchland.ibm.com/fs/u1/ldw/Python-1.5.2/Modules'] >>> Any suggestions? Larry

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PEP 372 -- Adding an ordered directory to collections
by Armin Ronacher Aug. 7, 2011

Aug. 7, 2011

Abstract ======== This PEP proposes an ordered dictionary as a new data structure for the ``collections`` module, called "odict" in this PEP for short. The proposed API incorporates the experiences gained from working with similar implementations that exist in various real-world applications and other programming languages. Rationale ========= In current Python versions, the widely used built-in dict type does not specify an order for the key/value pairs stored. This makes it hard to use dictionaries as data storage for some specific use cases. Some dynamic programming languages like PHP and Ruby 1.9 guarantee a certain order on iteration. In those languages, and existing Python ordered-dict implementations, the ordering of items is defined by the time of insertion of the key. New keys are appended at the end, keys that are overwritten and not moved. The following example shows the behavior for simple assignments: >>> d = odict() >>> d['parrot'] = 'dead' >>> d['penguin'] = 'exploded' >>> d.items() [('parrot', 'dead'), ('penguin', 'exploded')] That the ordering is preserved makes an odict useful for a couple of situations: - XML/HTML processing libraries currently drop the ordering of attributes, use a list instead of a dict which makes filtering cumbersome, or implement their own ordered dictionary. This affects ElementTree, html5lib, Genshi and many more libraries. - There are many ordererd dict implementations in various libraries and applications, most of them subtly incompatible with each other. Furthermore, subclassing dict is a non-trivial task and many implementations don't override all the methods properly which can lead to unexpected results. Additionally, many ordered dicts are implemented in an inefficient way, making many operations more complex then they have to be. - PEP 3115 allows metaclasses to change the mapping object used for the class body. An ordered dict could be used to create ordered member declarations similar to C structs. This could be useful, for example, for future ``ctypes`` releases as well as ORMs that define database tables as classes, like the one the Django framework ships. Django currently uses an ugly hack to restore the ordering of members in database models. - Code ported from other programming languages such as PHP often depends on a ordered dict. Having an implementation of an ordering-preserving dictionary in the standard library could ease the transition and improve the compatibility of different libraries. Ordered Dict API ================ The ordered dict API would be mostly compatible with dict and existing ordered dicts. (Note: this PEP refers to the Python 2.x dictionary API; the transfer to the 3.x API is trivial.) The constructor and ``update()`` both accept iterables of tuples as well as mappings like a dict does. The ordering however is preserved for the first case: >>> d = odict([('a', 'b'), ('c', 'd')]) >>> d.update({'foo': 'bar'}) >>> d collections.odict([('a', 'b'), ('c', 'd'), ('foo', 'bar')]) If ordered dicts are updated from regular dicts, the ordering of new keys is of course undefined again unless ``sort()`` is called. All iteration methods as well as ``keys()``, ``values()`` and ``items()`` return the values ordered by the the time the key-value pair was inserted: >>> d['spam'] = 'eggs' >>> d.keys() ['a', 'c', 'foo', 'spam'] >>> d.values() ['b', 'd', 'bar', 'eggs'] >>> d.items() [('a', 'b'), ('c', 'd'), ('foo', 'bar'), ('spam', 'eggs')] New methods not available on dict: ``odict.byindex(index)`` Index-based lookup is supported by ``byindex()`` which returns the key/value pair for an index, that is, the "position" of a key in the ordered dict. 0 is the first key/value pair, -1 the last. >>> d.byindex(2) ('foo', 'bar') ``odict.sort(cmp=None, key=None, reverse=False)`` Sorts the odict in place by cmp or key. This works exactly like ``list.sort()``, but the comparison functions are passed a key/value tuple, not only the value. >>> d = odict([(42, 1), (1, 4), (23, 7)]) >>> d.sort() >>> d collections.odict([(1, 4), (23, 7), (42, 1)]) ``odict.reverse()`` Reverses the odict in place. ``odict.__reverse__()`` Supports reverse iteration by key. Questions and Answers ===================== What happens if an existing key is reassigned? The key is not moved but assigned a new value in place. This is consistent with existing implementations and allows subclasses to change the behavior easily:: class movingcollections.odict): def __setitem__(self, key, value): self.pop(key, None) odict.__setitem__(self, key, value) What happens if keys appear multiple times in the list passed to the constructor? The same as for regular dicts: The latter item overrides the former. This has the side-effect that the position of the first key is used because the key is actually overwritten: >>> odict([('a', 1), ('b', 2), ('a', 3)]) collections.odict([('a', 3), ('b', 2)]) This behavior is consistent with existing implementations in Python, the PHP array and the hashmap in Ruby 1.9. Why is there no ``odict.insert()``? There are few situations where you really want to insert a key at an specified index. To avoid API complication, the proposed solution for this situation is creating a list of items, manipulating that and converting it back into an odict: >>> d = odict([('a', 42), ('b', 23), ('c', 19)]) >>> l = d.items() >>> l.insert(1, ('x', 0)) >>> odict(l) collections.odict([('a', 42), ('x', 0), ('b', 23), ('c', 19)]) Example Implementation ====================== A poorly performing example implementation of the odict written in Python is available: `odict.py <http://dev.pocoo.org/hg/sandbox/raw-file/tip/ odict.py>`_ The version for ``collections`` should be implemented in C and use a linked list internally. Other implementations of ordered dicts in various Python projects or standalone libraries, that inspired the API proposed here, are: - `odict in Babel`_ - `OrderedDict in Django`_ - `The odict module`_ - `ordereddict`_ (a C implementation of the odict module) - `StableDict`_ - `Armin Rigo's OrderedDict`_ .. _odict in Babel: http://babel.edgewall.org/browser/trunk/babel/util.py?rev=374#L178 .. _OrderedDict in Django: http://code.djangoproject.com/browser/django/trunk/django/utils/datastructu… .. _The odict module: http://www.voidspace.org.uk/python/odict.html .. _ordereddict: http://www.xs4all.nl/~anthon/Python/ordereddict/ .. _StableDict: http://pypi.python.org/pypi/StableDict/0.2 .. _Armin Rigo's OrderedDict: http://codespeak.net/svn/user/arigo/hack/pyfuse/OrderedDict.py Future Directions ================= With the availability of an ordered dict in the standard library, other libraries may take advantage of that. For example, ElementTree could return odicts in the future that retain the attribute ordering of the source file. Copyright ========= This document has been placed in the public domain.

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Turtle graphics speed(). Seems broken
by Alexander.Oot＠gmail.com Feb. 27, 2010

Feb. 27, 2010

I think the speed function may be broken from the turtle graphics package "from turtle import * speed('fastest') forward(50)" I have tried all of the different speed settings, but I get no change in the turtle's speed.... does anyone know how to fix this?

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socket.inet_ntop, and pton question
by Andrew Aug. 5, 2009

Aug. 5, 2009

Hi Are these functions (inet_ntop(), inet_pton()) from the socket library supported on Windows. If not is there an equivalent for them using Windows Ive seen mention of people creating their own in order to use them Appreciate the help ty

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Proposal: Decimal literals in Python.
by Lennart Benschop July 14, 2009

July 14, 2009

Python has had the Decimal data type for some time now. The Decimal data type is ideal for financial calculations. Using this data type would be more intuitive to computer novices than float as its rounding behaviour matches more closely what humans expect. More to the point: 0.1 and 0.01 are exact in Decimal and not exact in float. Unfortunately it is not very easy to access the Decimal data type. To obtain the decimal number 12.34 one has to do something like this: import decimal x=decimal.Decimal("12.34") Of course we can intruduce a single character function name as an alias for the Decimal type constructor, but even then we have to use both parentheses and quotes for each and every decimal constant. We cannot make it shorter than D("12.34") With Python 3000 major changes to the language are carried out anyway. My proposal would require relatively minor changes. My proposal: - Any decimal constant suffixed with the letter "D" or "d" will be interpreted as a literal of the Decimal type. This also goes for decimal constants with exponential notation. Examples of decimal literals: 1d 12.34d 1e-3d (equivalent to 0.001d) 1e3d (same value as 1000d, but without trailing zeros). 1.25e5d (same value as 125000d but without trailing zeros). When we print a decimal number or convert it to a string with str(), a trailing d should not be added. The repr function does yield strings with a trailing d. When decimal numbers are converted from strings, both numbers with and without a trailing d should be accepted. If we have decimal literals in the core language, we should probably have a type constructor in the core namespace, e.g. dec() along with int() and float(). We then need the decimal module only for the more advanced stuff like setcontext. Pros: - the Decimal data type will be more readily accessible, especially for novices. - Traling characters at the end of a literal are already used (the L for long). - It does not conflict with the syntax of other numeric constants or language constructs. - It does not change the meaning of existing valid literal constants. Constants that used to be float will continue to do so. Cons: - The lexical scanner of the Python interpreter will be slightly more complex. - The d suffix for constants with exponential notation is ugly. - Decimal numbers with exponentail notation like 2e5d could be mistaken for hex (by humans, not by the parser as hex requires the 0x prefix). - It requires the decimal module to be part of the core Python interpreter. -- Lennart

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Re: renice
by Dan July 14, 2009

July 14, 2009

On Oct 26, 4:30 am, mokhtar <mbmessa...(a)yahoo.com> wrote: > Hi > > Is it possible to renice the python process executing the current python > script ?:confused: > -- > View this message in context:http://www.nabble.com/renice-tf4695834.html#a13422771 > Sent from the Python - python-list mailing list archive at Nabble.com. On UNIX: >>> import os >>> os.system("renice -n %d %d" % ( new_nice, os.getpid() ) ) (untested) I don't know if windows has the concept of renice... -Dan

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Unable to abort a FTP command?
by _wdx＠163.com April 15, 2009

April 15, 2009

Hi, I write the following script to retrieve a part of a large file from a FTP site: import ftplib class ftp_getter(object): def __init__(self): self.handle = ftplib.FTP('ftp_server_address') self.handle.set_debuglevel(2) self.login() def login(self): self.handle.login('user', 'pass') self.handle.cwd('/temp1/') def quit(self, is_close = False): self.handle.quit() if is_close: self.handle.close() print 'ftp handle closed' def getpart_callback(self, received): print "received a packet" if self.cnt <= 0: if not self.outf.closed: self.outf.close() if not self.aborted: try: self.handle.abort() self.aborted = True except Exception,ex: pass else: print 'received packet, [0] = %x' % ord(received[0]) self.outf.write(received) self.cnt -= len(received) def getpart(self, ftp_filename, rest, cnt, out_filename): self.outf = open(out_filename, 'wb') self.cnt = cnt self.aborted = False self.handle.retrbinary('RETR ' + ftp_filename, self.getpart_callback, 8192, rest) if not self.outf.closed: self.outf.close() if __name__ == '__main__': g = ftp_getter() g.getpart('FILE_TO_RETRIEVE.DAT', 50000, 20, 'out.dat') g.quit(True) print "all done." As the last four lines shown, I want to connect to my FTP server, retrieve 20 bytes starting at offset 50000 from FILE_TO_RETRIEVE.DAT, and stop retrieving after more than 20 bytes have been received. It's quite simple, but to my suprise, this code does not work. "self.handle.abort()" have been executed and I got the expected response from server(426), but the RETR command does not seem to stop at all. More and more data are received and getpart_callback method is called again and again. Why the RETR command is not actually aborted? Can anyone help me? Thanks Xu Wang

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