Re: Can Python function return multiple data?
Am 03.06.2015 um 01:56 schrieb Chris Angelico: and it's pretty convenient. In C, the nearest equivalent is passing a number of pointers as parameters, and having the function fill out values. Python's model is a lot closer to what you're saying than C's model is :) At least, C functions can return structs... Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: subprocess.Popen zombie
Am 20.05.2015 um 18:44 schrieb Robin Becker: not really, it's just normal to keep event routines short; the routine which beeps is after detection of the cat's entrance into the house and various recognition schemes have pronounced intruder :) You could add a timed "cleanup" routine which .wait()s after a certain time (250 ms or so). Or even better, which .poll()s and re-schedules itself if the process still runs. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: Why does the first loop go wrong with Python3
Am 19.05.2015 um 15:16 schrieb Oscar Benjamin: However the normal way to do this is to iterate over stdout directly: Depends. There may be differences when it comes to buffering etc... Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: Rule of order for dot operators?
Am 16.05.2015 um 21:20 schrieb C.D. Reimer:
Does python perform the dot operators from left to right or according to
a rule of order (i.e., multiplication/division before add/subtract)?
In this case, it does the only thing it can do:
title = slug.replace('-',' ').title()
is performed as
* take slug
* get its replace method
* call it and take the result
* get this result's title method
* call it and store its result into title.
OTOH,
title = slug.title().replace('-',' ')
is performed as
* take slug
* get its title method
* call it and take the result
* get this result's replace method
* call it and store its result into title.
Any other order would be unintuitive and just wrong.
The reason why the result is the same is because .title() title-cases
letters after a space as well as after a '-'.
In other cases, it wouldn't do so, so you have to take care what you do.
Thomas
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Re: Basic misunderstanding on object creation
Am 13.05.2015 um 15:25 schrieb andrew cooke:
class Foo:
... def __new__(cls, *args, **kargs):
... print('new', args, kargs)
... super().__new__(cls, *args, **kargs)
new (1,) {}
Traceback (most recent call last):
File "", line 1, in
File "", line 4, in __new__
TypeError: object() takes no parameters
object's __new__() dosn't take any parameters. So call it without arguments:
class Foo:
def __new__(cls, *args, **kargs):
print('new', args, kargs)
super().__new__(cls)
(at least if we know that we inherit from object. Might be that this one
doesn't work very good with multiple inheritance...)
Thomas
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Re: Python Worst Practices
Am 26.02.2015 01:37 schrieb Chris Angelico: My bad. I was talking in a context of Python programming, specifically with APIs where you would use some kind of true/false flag as either a function parameter or a return value. Oh. Then take subprocess.Popen.wait()... :-P Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: Md5 is different in Windows and Linux
Am 02.03.2015 20:14 schrieb sohcahto...@gmail.com:
On Monday, March 2, 2015 at 12:43:59 AM UTC-8, Sarvagya Pant wrote:
f = open("somefile.txt")
This one is the problem. Under Windows, you have to open the file in
binary to avoid that something "bad" happens with it.
So just do
f = open("somefile.txt", "rb")
and you should be fine.
I don't know which is worse, the fact that you're composing your message in
HTML, or the fact that you're using Comic Sans as your font.
#2 wouldn't be possible without #1...
Thomas
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Re: why can't download file from linux server into local window disk c:
Am 08.12.2014 19:11 schrieb Luuk: > no, it's the ssh-server denying a log on from 'root' You are repating yourself. How could possibly with open(localpath, 'wb') as fl: PermissionError: [Errno 13] Permission denied: 'c:' be a problem with the SSH server? --- SoupGate-Win32 v1.05 * Origin: nntp.gatew...@.piz.noip.me> (1:249/999) --- Synchronet 3.15b-Win32 NewsLink 1.92 SpaceSST BBS Usenet <> Fidonet Gateway -- https://mail.python.org/mailman/listinfo/python-list
Re: why can't download file from linux server into local window disk c:
Am 09.12.2014 09:14 schrieb pengsir: > My vps ip is x.y.z.w ,i want to download /etc/passwd from linux server > into my local window disk c: . > localpath = 'c:' [...] > with open(localpath, 'wb') as fl: > PermissionError: [Errno 13] Permission denied: 'c:' That's completely clear: you are not allowed to create a file named 'c:'. You should replace it with a full path name, such as localpath = 'c:\\passwd' or such. Thomas --- SoupGate-Win32 v1.05 * Origin: nntp.gatew...@.piz.noip.me> (1:249/999) --- Synchronet 3.15b-Win32 NewsLink 1.92 SpaceSST BBS Usenet <> Fidonet Gateway -- https://mail.python.org/mailman/listinfo/python-list
Re: Question on lambdas
Am 09.12.2014 04:09 schrieb memilanuk:
so in the first example in my original post:
...
lambda: update_label2('A', 100)
would this work the same? It looks as though it'd be passing the same
two parameters to the same function...
lambda: 'A', 100: update_label2()
No. Even if it would be allowed by syntax, how should 'A', 100 be passed
to update_label2() if it is not written inside its ()s?
Also, in my second example:
class MyText(Text):
def __init__(self, master, **kw):
apply(Text.__init__, (self, master), kw)
self.bind("", lambda e: "break")
I'm kind of missing what 'e' is and where its defined and what it's
supposed to be passing to "break"...?
Passing to "break"? A string cannot be passed anything.
What bind() expects is any callable which takes an event object (IIRC).
As you don't need any information from the event object here, you can
ignore it (but it must be oresent, otherwise the call would fail).
What the function does is just return "break". What sense this should
have is unclear to me; probably the return value is just ignored.
I was reading in 'Programming Python 4th ed' by Lutz and he talks about
something to do with default values vs. enclosing scopes... that
something like:
lambda x=x: some_expr
when evaluated inside a function loop to create buttons, etc., causes
'x' to be evaluated as the default value at the function creation time,
vs. when the function is actually called. Do I have that more or less
correct?
Yes. This one takes the current value of x inside the function.
Compare these:
x = 4
f1 = lambda: x
x = 5
f2 = lambda: x
x = 42
print f1(), f2()
What could one expect? "4 5", maybe. What does one get? "42 42". Why?
Because the x is evaluated at the time it is indeed called.
We can work around this with
x = 4
f1 = lambda y=x: y
x = 5
f2 = lambda y=x: y
x = 42
print f1(), f2()
(you can take x for y here, but this one is better understandable)
Here each of the function gets the respective value "tattooed in"; we
get "4 5" indeed as output.
Downside is that we have the possibility to do print f1(123) which
indeed gives 123.
If we want to disallow this kind of calls, we could do
def create_const_function(val):
def inner_function():
return val
or just
create_const_function = lambda val: lambda: val
and then
f1 = create_const_function(4)
f2 = create_const_function(5)
print f1(), f2()
et voilà.
Thomas
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Re: why can't download file from linux server into local window disk c:?
Am 08.12.2014 19:11 schrieb Luuk: no, it's the ssh-server denying a log on from 'root' You are repating yourself. How could possibly with open(localpath, 'wb') as fl: PermissionError: [Errno 13] Permission denied: 'c:' be a problem with the SSH server? -- https://mail.python.org/mailman/listinfo/python-list
Re: why can't download file from linux server into local window disk c:?
Am 09.12.2014 09:14 schrieb pengsir: My vps ip is x.y.z.w ,i want to download /etc/passwd from linux server into my local window disk c: . localpath = 'c:' [...] with open(localpath, 'wb') as fl: PermissionError: [Errno 13] Permission denied: 'c:' That's completely clear: you are not allowed to create a file named 'c:'. You should replace it with a full path name, such as localpath = 'c:\\passwd' or such. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: io.UnsupportedOperation: fileno
Am 14.11.2014 00:42 schrieb satishmlm...@gmail.com: fileno() in not supported. Is it only in 3.1? What is the workaround? You have been asked many times about the details of your environment. Especially, you have been told that it is important to know if you directly use the Python CLI or some GUI like IDLE. I just tested the latter thing and found out that it indeed makes a difference, as it introduces a replacement for the std* stuff you are missing: >>> sys.stdin >>> sys.stdout >>> sys.stderr Calling .fileno() on such a Pseudo*File just raises an UnsupportedOperation exception. This is in contrast to using the CLI directly. -- https://mail.python.org/mailman/listinfo/python-list
Re: %%(%s)s mean in python
Am 29.10.2014 07:02 schrieb satishmlm...@gmail.com:
What does %%(%s)s mean in Python?
Weird question, as this has nothing to do with the code you just posted.
In general, what comes up to my mind, is that it is a format string to
build another format string.
Example:
metafmt = '%%(%s)s'
fieldname = 'myfield'
fmt = metafmt % fieldname
# Now we have a fmt as if it was assigned with '%(myfield)s':
# %% -> %, %s -> myfield.
d = {fieldname: 'my content'}
print fmt % d
# this now prints the given field - which is noted in fieldname -
# from the given dict d.
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Re: Iterator, modify data in loop body
Am 13.09.2014 09:22 schrieb Chris Angelico: In that case, don't iterate over the list at all. Do something like this: while lst: element = lst.pop(0) # work with element lst.append(new_element) And if you don't like that, define a def iter_pop(lst): while lst: yield lst.pop(0) and you can do for element in iter_pop(lst): # work with element lst.append(new_element) Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: Thread-ID - how much could be?
Am 11.09.2014 23:32 schrieb Ervin Hegedüs: There is no upper limit to the thread name other than that you will eventually run out of memory ;) thanks - I hope that the memory will not run out by these threads... :) Anyway, that means, on my system: import sys print sys.maxint 9223372036854775807 the couter could be 9223372036854775807? And after? :) After that, the couter magically turns into a long and it goes on. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: 'is not' or '!='
Am 20.08.2014 13:17 schrieb Chris Angelico: That's true, but how easy is it to annotate a file with each line's author (or, at least, to figure out who wrote some particular line of code)? It's easy enough with 'git blame' or 'hg blame', and it wouldn't surprise me if bzr had a similar feature; but that's all the current generation of version control systems. I don't think cvs or svn offered that kind of feature. $ LANG=C svn help blame blame (praise, annotate, ann): Output the content of specified files or URLs with revision and author information in-line. usage: blame TARGET[@REV]... $ cvs help Unknown command: `help' CVS commands are: add Add a new file/directory to the repository adminAdministration front end for rcs annotate Show last revision where each line was modified [...] IMHO annotate does the same what blame does on other VCS. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: 'is not' or '!='
Am 18.08.2014 22:53 schrieb Marko Rauhamaa: Frankly, I don't know of any other object that is "==" to the None object except None itself, but such objects could possible exist. class ImitatingNone(object): def __eq__(self, other): return True # is equal to everything else return other is None # is equal only to None return not(other) # is equal to everything which is falsey Pick one. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: 'is not' or '!='
Am 19.08.2014 00:04 schrieb Chris Kaynor: In each of these cases, the behavior may be different in other implementations or versions of Python. And, the most important thing, in each of these cases, using "is" is semantically wrong, so no matter how different versions behave. If you ask the wrong question, you might get a wrong answer. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: Iterating through set
Am 15.07.2014 02:10 schrieb LJ: Hi All. I'm coding a Dynamic Programming algorithm to solve a network flow problem. At some point in the algorithm I have to iterate through a set of nodes, while adding and/or removing elements, until the set is empty. I know a regular set() object does not work in a case like this, so I wonder if anyone knows of an efficient pythonic way to handle this. Thanks in advance! This sounds like you want to avoid processing of an item as soon as it is removed. Then I'd suggest the following: add = set() remove = set() while myset or add: for item in myset: if item not in remove: # process myset -= remove myset += add remove.clear() add.clear() Adding happens via add.add(item), removing via remove.add(item). If there is additionally the need to take care in which order to apply add/remove, or if it can happen that item X is added and removed in the same loop run, it gets a bit more complicated. Then adding would be like if item in remove: remove.remove(item) elif item not in myset and item not in add: add.add(item) and removing like if item in add: add.remove(item) elif item in myset: remove.add(item) HTH, Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: Python's re module and genealogy problem
Am 11.06.2014 14:23 schrieb BrJohan:
Can it, for a pair of regular expressions be decided whether at least
one string matching both of those regular expressions, can be constructed?
If it is possible to make such a decision, then how? Anyone aware of an
algorithm for this?
Just a feeling-based statement: I don't think that is easily possible.
Every RE can potentially match an infinite number of statements.
Just have a look at
re1 = re.compile('A43.*')
re2 = re.compile('.*[0-9][A-F]')
It can easily seen that the area these REs work on is different; they
are orthogonal.
So there is an infinite number of strings these REs match.
Thomas
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Re: try/except/finally
Am 08.06.2014 05:58 schrieb Rustom Mody: Some people¹ think that gotos are a code-smell. ¹ I am not exactly those people. A chap called E W Dijkstra made the statement: "Goto statement considered harmful" and became famous. And became widely misunderstood. If anybody would read the whole what he wrote, people would learn that he doesn't criticise the *use* of goto, but he wants the *replacement* of goto with something else (like exceptions). As C doesn't have exceptions, goto is in many cases the simplest and easiest way of handling errors. Essentially, you can write both good and bad code both with and without goto. Thomaas -- https://mail.python.org/mailman/listinfo/python-list
Re: Python 3 __bytes__ method
Am 12.01.2014 01:24 schrieb Ethan Furman: I must admit I'm not entirely clear how this should be used. Is anyone using this now? If so, how? I am not, as I currently am using Py2, but if I would, I would do it e. g. for serialization of objects in order to send them over the line or to save them into a file. IOW, the same purpose as we havd on __str__ in Py2. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: 'Straße' ('Strasse') and Python 2
Am 13.01.2014 10:54 schrieb wxjmfa...@gmail.com: Not at all. I'm afraid I'm understanding Python (on this aspect very well). IBTD. Do you belong to this group of people who are naively writing wrong Python code (usually not properly working) during more than a decade? Why should I be? 'ß' is the the fourth character in that text "Straße" (base index 0). Character-wise, yes. But not byte-string-wise. In a byte string, this depends on the character set used. On CP 437, 850, 12xx (whatever Windows uses) or latin1, you are right, but not on the widely used UTF8. sys.version '2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)]' assert 'Straße'[4] == 'ß' assert u'Straße'[4] == u'ß' Linux box at home: Python 2.7.3 (default, Apr 14 2012, 08:58:41) [GCC] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> assert 'Straße'[4] == 'ß' Traceback (most recent call last): File "", line 1, in AssertionError >>> assert u'Straße'[4] == u'ß' Python 3.3.0 (default, Oct 01 2012, 09:13:30) [GCC] on linux Type "help", "copyright", "credits" or "license" for more information. >>> assert 'Straße'[4] == 'ß' >>> assert u'Straße'[4] == u'ß' Windows box at work: Python 2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> assert 'Straße'[4] == 'ß' >>> assert u'Straße'[4] == u'ß' PS Nothing to do with Py2/Py3. As bytes and unicode and str stuff is heavily changed between them, of course it has to do. And I think you know that and try to confuse and FUD us all - with no avail. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: 'Straße' ('Strasse') and Python 2
Am 12.01.2014 08:50 schrieb wxjmfa...@gmail.com: sys.version 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)] s = 'Straße' assert len(s) == 6 assert s[5] == 'e' Wow. You just found one of the major differences between Python 2 and 3. Your assertins are just wrong, as s = 'Straße' leads - provided you use UTF8 - to a representation of 'Stra\xc3\x9fe', obviously leading to a length of 7. Thomas -- https://mail.python.org/mailman/listinfo/python-list
Re: New user's initial thoughts / criticisms of Python
Am 09.11.2013 14:27 schrieb Joshua Landau: `select` is quite an odd statement, in that in most cases it's just a weaker variant of `if`. By the time you're at the point where a `select` is actually more readable you're also at the point where a different control flow is probably a better idea. Things like dictionaries or a variables pointing to functions are really useful and can be encapsulated in a class quite well. This is a bit more advanced but largely more rigorous. class Switch(object): def __init__(self, value): self.value = value self.called = False def case(self, other): def wr(func): if not self.called and self.value == other: self.called = True return func(self.value) return wr def default(self, func): if not self.called: self.called = True return func(self.value) if __name__ == '__main__': import random while 1: n = random.randrange(0, 5) sw = Switch (n) @sw.case(1) def _(n): print n, "is one" @sw.case(2) def _(n): print n, "is two" @sw.default def _(n): print n, "is something else" -- https://mail.python.org/mailman/listinfo/python-list
Re: Is there a function that applies list of functions to a value?
Am 2013-08-28 14:52 schrieb AdamKal: Hi, From time to time I have to apply a series of functions to a value in such a way: func4(func3(func2(func1(myval I was wondering if there is a function in standard library that would take a list of functions and a initial value and do the above like this: func_im_looking_for([func1, func2, func3, func4], myval) I looked in itertools but nothing seamed to do the job. This seams like something vary obvious that was needed many times elsewhere so maybe you could help me? reduce(lambda x, f: f(x), funcs, myval) would do the job. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: A certainl part of an if() structure never gets executed.
Am 12.06.2013 03:46 schrieb Rick Johnson: On Tuesday, June 11, 2013 8:25:30 PM UTC-5, nagia@gmail.com wrote: is there a shorter and more clear way to write this? i didnt understood what Rick trie to told me. My example included verbatim copies of interactive sessions within the Python command line. You might understand them better if you open the Python command line and type each command in one-by-one. Here is an algoritm that explains the process: open_command_window() whilst learning or debugging: type_command() press_enter() observe_output() if self.badder.is_full: take_potty_break() close_command_window() with command_window(): whilst learning or debugging: type_command() press_enter() observe_output() if self.badder.is_full: take_potty_break() looks nicer. SCNR Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Piping processes works with 'shell = True' but not otherwise.
Am 27.05.2013 02:14 schrieb Carlos Nepomuceno: pipes usually consumes disk storage at '/tmp'. Good that my pipes don't know about that. Why should that happen? Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: object.enable() anti-pattern
Am 10.05.2013 15:22 schrieb Roy Smith:
That's correct. But, as described above, the system makes certain
guarantees which allow me to reason about the existence or non-existence
os such entries.
Nevertheless, your 37 is not a FD yet.
Let's take your program:
#include
#include
#include
#include
int main(int argc, char** argv) {
int max_files = getdtablesize();
assert(max_files >= 4);
Until here, the numbers 3 toll max_files may or may not be FDs.
for (int i = 3; i < max_files; ++i) {
close(i);
}
Now they are closed; they are definitely no longer FDs even if they
were. If you would use them in a file operation, you'd get a EBADF which
means "fd is not a valid file descriptor".
dup(2);
From now on, 3 is a FD and you can use it as such.
char* message = "hello, fd world\n";
write(3, message, strlen(message));
}
No, what I've done is taken advantage of behaviors which are guaranteed
by POSIX.
Maybe, but the integer numbers get or los their property as a file
descriptor with open() and close() and not by assigning them to an int.
Thomas
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Re: Style question -- plural of class name?
Am 09.05.2013 02:38 schrieb Colin J. Williams: On 08/05/2013 4:20 PM, Roy Smith wrote: "A list of FooEntry's" +1 Go back to school. Both of you... That is NOT the way to build a plural form... Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: is "_io.py" missing from 2.7.4 ?
Am 08.04.2013 15:42 schrieb dbv: Ah, okay. Then on Windows, _io.pyd should be in the /DLLs folder but it isn't there ? It seems to be a built-in module: >>> import _io >>> _io alike to >>> import __builtin__ >>> __builtin__ as opposed to >>> import win32ui >>> win32ui 'C:\Python27\lib\site-packages\Pythonwin\win32ui.pyd'> and >>> import os >>> os Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: del not working for (exhausted) dict iterable value (Python 3.3)
Am 12.03.2013 06:52 schrieb alex23: You're effectively doing this: event = dict(Items=[1,2,3]) for e in event['Items']: ... del event['Items'] ... Traceback (most recent call last): File "", line 2, in KeyError: 'Items' You want to move your del statement up an indentation level so it happens after the iterator is actually exhausted, and not after the first iteration. Just to be clear: Exhausting the iterator is not the problem, as I thought as well at the first glance. The problem is the fact that the loop body tuns multiple times - and so does the del statement. A event = dict(Items=[1,2,3]) for e in event['Items']: if 'Items' in event: del event['Items'] runs perfectly, as the iterable is transformed to an iterator at the very start of the loop. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: This mail never gets delivered. Any ideas why?
Am 10.03.2013 19:39 schrieb Νίκος Γκρ33κ: Hey man this worked via Python! [...] if( os.system( 'echo "%s" | mail -s "%s" supp...@superhost.gr' % (MESSAGE, FROM) ) ): [...] Thank you! I beleive this is the simplest way of sending an email! Until you get a MESSAGE which has a " sign in it, or a FROM. (Sorry, didn't see this message before.) In order to prevent trouble with this, it might be better to use subprocess and to do sp = subprocess.Popen(['mail', '-f', FROM, '-s', SUBJECT, 'supp...@superhost.gr], stdin=subprocess.PIPE) sp.communicate(MESSAGE) res = sp.wait() if res: ... else: ... If you do so, you can have FROMs, SUBJECTs and MESSAGEs conaining every character you want, including " and ', an no shell will complain about it or be confused. (Note that I changed the arguments for mail a little bit, because -s prevedes the subject and -f the from.) Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: This mail never gets delivered. Any ideas why?
Am 11.03.2013 10:15 schrieb nagia.rets...@gmail.com: Thank you Thomas but that simple line as i have it now its capable of sending mail successfully Obviously not, otherwise you wouldn't ask, would you? Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: This mail never gets delivered. Any ideas why?
Am 11.03.2013 06:47 schrieb Thomas Rachel:
# either
message.add_header('Subject', email.quoprimime.header_encode(SUBJECT))
# or
message.add_header('Subject', email.base64mime.header_encode(SUBJECT))
Sorry! These were completely wrong.
# either
message.add_header('Subject', email.quoprimime.header_encode(SUBJECT,
charset='utf8'))
# or
message.add_header('Subject', email.base64mime.header_encode(SUBJECT,
charset='utf8'))
should be correct, however.
But be aware that both seem to potentially break the UTF8 surrogates
apart, which in turn confuses at least Thunderbird, so it might not be
the ideal solution.
Maybe you transcode the subject into iso-8859-7 and declare it as such,
if you only have greek characters.
Let's try:
[...]
# and then
# either
enc = email.base64mime.header_encode
# or
enc = email.quoprimime.header_encode
message.add_header('Subject', enc(
SUBJECT.decode('utf8').encode('iso-8859-7'),
charset='iso-8859-7'))
I tried both values for enc(), and both seem to work with the subject
string you provided.
HTH,
Thomas
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Re: This mail never gets delivered. Any ideas why?
Am 11.03.2013 06:25 schrieb Thomas Rachel:
1. Your subject is not properly encoded.
All characters outside the ASCII area must be encoded in an appropriate
way if you send an email. It MIGHT be the case that sendmail handles
this for you, but probably not every version.
Mine not, at least.
So you should do this:
import email
message = email.message_from_string('')
message.add_header('From', FROM)
message.add_header('To', ", ".join(TO))
# and then
# either
message.add_header('Subject', email.quoprimime.header_encode(SUBJECT))
# or
message.add_header('Subject', email.base64mime.header_encode(SUBJECT))
# Here you should decide upon readability: for Greek text, base64 is
# probably better, while for languages with Latin characters, quopri
# is better because bost characters remain readable.
#
# The difference is
#
# Subject:
=?iso-8859-1?q?=CE=95=CF=80=CE=B9=CE=BA=CE=BF=CE=B9=CE=BD=CF=89=CE=BD=CE?=
# =?iso-8859-1?q?=AF=CE=B1_=CF=80=CE=B9=CE=B8=CE=B1=CE=BD=CE=BF=CF=8D_=CF?=
# =?iso-8859-1?q?=80=CE=B5=CE=BB=CE=AC=CF=84=CE=B7!?=
#
# vs.
#
# Subject:
=?iso-8859-1?b?zpXPgM65zrrOv865zr3Pic69zq/OsSDPgM65zrjOsc69zr/PjSDPgM61zrs=?=
# =?iso-8859-1?b?zqzPhM63IQ==?=
#
#
# If your sender or your recipients have names outside the ASCII area,
# you should quote them as well.
# These are for the text.
message.add_header('MIME-Version', '1.0')
message.add_header('Content-Type', 'text/plain; charset=utf8')
message.add_header('Content-Transfer-Encoding', '8bit')
message.set_payload(TEXT)
# now transform the object into a string:
message = message.as_string()
print message
This message string now can be used for sending.
HTH,
Thomas
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Re: This mail never gets delivered. Any ideas why?
Am 09.03.2013 22:20 schrieb Νίκος Γκρ33κ:
SENDMAIL = '/usr/sbin/sendmail'
FROM = mail
TO = ['supp...@superhost.gr']
SUBJECT = "Επικοινωνία πιθανού πελάτη!"
TEXT = comment
message = """\
From: %s
To: %s
Subject: %s
%s
""" % (FROM, ", ".join(TO), SUBJECT, TEXT)
p = os.popen("%s -t -i" % SENDMAIL, "w")
p.write(message)
status = p.close()
if status != 256:
print( "Ευχαριστώ πολύ για το ενδιαφέρον! Θα
επικοινωνήσω μαζί σου άμεσα :-)" )
else:
print( "Δυστυχώς δεν μπόρεσε να
αποσταλεί το e-mail :-(" )
===
Do you see somehtign wrong in the above code?
I see some things here:
1. Your subject is not properly encoded.
All characters outside the ASCII area must be encoded in an appropriate
way if you send an email. It MIGHT be the case that sendmail handles
this for you, but probably not every version.
But that should not prevent sending the mail at all; probably some
garbage would result.
2. You failed to tell us what "never gets delivered" means: do you get
an error message?
3. You failed to give us a SSCCE
Re: "The urlopen() and urlretrieve() functions can cause arbitrarily long delays"
Am 24.02.2013 20:27 schrieb 7segment: When in doubt, check some other way, such as with a browser. Thank you Ian. Browser is not a good idea, because I need this tool to work automatically. I don't have time to check and compare the response times manually and put them into the database. Of course not for the long term. But you could check e.g. if MSN needs 60 s as well from the browser. If not, there could be something else wrong. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: improving performance of writing into a pipe
Am 18.02.2013 17:31 schrieb mikp...@gmail.com:
However I get an exception while trying to open the queue:
fout = open('/tmp/mypipe', 'w')
I don't see an exception in your answer. Where did you put it for us?
I have tried it in a command line and the call doesn't return until in another
terminal I open the same queue for reading (???)
That's normal. An open call to a pipe blocks until someone reads from it.
But it's the same with your popen() version.
Thomas
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Re: inheritance and how to use it
Am 15.02.2013 17:59 schrieb Bob Brusa:
Hi,
I use a module downloaded from the net. Now I want to build my own
class, based on the class SerialInstrument offered in this module - and
in my class I would like to initialize a few things, using e. g. the
method clear() offered by SerialInstrument. Hence I type:
class myClass(SerialInstrument)
self.clear(self)
def f1(self, str1, str2)
...do something etc.
I then get the message "self not know" from the statement
self.clear(self).
Which is absolutely correct. Besides, I would have expected some syntax
errors.
You try to execute the clear() method during the definition of the
class, not during the instantiation.
Instantiation happens in the __init__() method.
You'll have to do it like this:
class myClass(SerialInstrument):
def __init__(self, *a, **k): # accept all parameters
super(myClass, self).__init__(*a, **k)
self.clear() # I don't think that self is to be given twice here...
def f1(self, str1, str2):
pass
I have tried many other notations - none worked. What
works is however the following code - specifying myClass without the
self.clear(self) in it:
x = myClass("argument")
x.clear()
Here the clear() is called on the object which has been created, so
after calling the __init__() above (which is, roughly, equivalent to
calling it at the bottom of __init__()).
Thomas
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Re: Implicit conversion to boolean in if and while statements
Am 10.02.2013 12:37 schrieb Steven D'Aprano:
So, in Python 4000, my vote is for set literals { } to create frozensets,
and if you want a mutable set, you have to use the set() type directly.
4000 sounds about long future.
In the meanwhile, a new syntax element could be introduced fpr
frozensets, such as {{ }} or something. (Although that might clutter
with a set containing a set.)
Thomas
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Re: Implicit conversion to boolean in if and while statements
Am 08.02.2013 07:29 schrieb Rick Johnson:
Consider this:
if connect("my:db") as db:
No need to make a call and then test for the validity of the call when you can
do both simultaneously AND intuitively.
Would be great, but can be emulated with
def ifiter(x):
if x: yield x
for db in ifiter(connect("my:db")):
Is not very intuitive, however, but does its job.
Thomas
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Re: i can't understand decorator
Am 15.01.2013 15:20 schrieb contro opinion:
>>> def deco(func):
... def kdeco():
... print("before myfunc() called.")
... func()
... print(" after myfunc() called.")
... return kdeco
...
>>> @deco
... def myfunc():
... print(" myfunc() called.")
...
>>> myfunc()
before myfunc() called.
myfunc() called.
after myfunc() called.
>>> deco(myfunc)()
before myfunc() called.
before myfunc() called.
myfunc() called.
after myfunc() called.
after myfunc() called.
Wrapping works this way:
The function is defined, and the wrapper replaces the function with a
different one which (in this case) calls the original one.
Try print(myfunc) here and you see that myfunc is only a name for
another function called kdeco. It is the one returned by the decorator.
1.
why there are two lines :before myfunc() called.and tow lines :after
myfunc() called. in the output?
This is because the "before" line is printed, then the modified "myfunc"
is called, which in turn prints another "before" line and then calls the
"really original" function. After it returns, the "after" line is called
by the inner placement function (the one which sticks at the myfunc
identifier). This function returns and the function instance which
called the first "before" line is printed then.
2.why the result is not
before myfunc() called.
myfunc() called.
after myfunc() called.
before myfunc() called.
myfunc() called.
after myfunc() called.
Because the function calls are wrapped and not repeated.
Thomas
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Re: please i need explanation
Am 11.01.2013 17:33 schrieb kwakukwat...@gmail.com: def factorial(n): if n<2: return 1 f = 1 while n>= 2: f *= n f -= 1 return f please it works. I doubt this. If you give n = 4, you run into an endless loop. but don’t get why the return 1 and the code below. The "if n < 2: return 1" serves to shorten the calculation process below. It is redundant, as you have a "f = 1" and a "return f" for n < 2. The code below first sets f, which holds the result, to 1 and then multiplies it by n in each step. As the loop should contain a 'n -= 1', n decreases by 1 every step, turning it into f = n * (n-1) * (n-2) * ... * 2 and then, as n is not >= 2 any longer, stops the loop, returning f. HTH, Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: How to modify this script?
Am 07.01.2013 18:56 schrieb Gertjan Klein:
(Watch out for line wraps! I don't know how to stop Thunderbird from
inserting them.)
Do "insert as quotation" (in German Thunderbird: "Als Zitat einfügen"),
or Strg-Shift-O. Then it gets inserted with a ">" before and in blue.
Just remove the > and the space after it; the "non-breaking property" is
kept.
Example:
columns = line.split("\t");
if len(columns) == 1:
output += ('' % max_columns) + line +
'\n'
continue
without and
columns = line.split("\t");
if len(columns) == 1:
output += ('' % max_columns) + line +
'\n'
continue
with this feature.
HTH,
Thomas
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Re: How to modify this script?
Am 06.01.2013 15:30 schrieb Kurt Hansen: Den 06/01/13 15.20, Chris Angelico wrote: On Mon, Jan 7, 2013 at 1:03 AM, Kurt Hansen wrote: I'm sorry to bother you, Chris, but applying the snippet with your code in Gedit still just deletes the marked, tab-separated text in the editor. Ah, whoops. That would be because I had a bug in the code (that's why I commented that it was untested). Sorry about that! Here's a fixed version: [cut]> Note that it's a single line: output += '' + item + ' ' If your newsreader (or my poster) wraps it, you'll need to unwrap that line, otherwise you'll get an IndentError. Ahhh, I did'nt realize that. Now it works :-) That version should work. It certainly does. I'll keep it and use it until at better solution is found. That would be simple: Replace output += '' + item + ' ' with if len(columns) >= 3: output += '' else: output += '' output += item + ' ' (untested as well; keep the indentation in mind!) Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: what’s the difference between socket.send() and socket.sendall() ?
Am 07.01.2013 11:35 schrieb iMath: what’s the difference between socket.send() and socket.sendall() ? It is so hard for me to tell the difference between them from the python doc so what is the difference between them ? and each one is suitable for which case ? The docs are your friend. See http://docs.python.org/2/library/socket.html#socket.socket.sendall | [...] Unlike send(), this method continues to send data from string | until either all data has been sent or an error occurs. HTH, Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: forking and avoiding zombies!
Am 11.12.2012 14:34 schrieb peter: On 12/11/2012 10:25 AM, andrea crotti wrote: Ah sure that makes sense! But actually why do I need to move away from the current directory of the parent process? In my case it's actually useful to be in the same directory, so maybe I can skip that part, or otherwise I need another chdir after.. You don't need to move away from the current directory. You cant use os to get the current work directory stderrfile = '%s/error.log' % os.getcwd() stdoutfile = '%s/out.log' % os.getcwd() ITYM os.path.join(os.getcwd(), 'error.log') resp. os.path.join(os.getcwd(), 'out.log') Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Confused compare function :)
Am 06.12.2012 09:49 schrieb Bruno Dupuis: The point is Exceptions are made for error handling, not for normal workflow. I hate when i read that for example: try: do_stuff(mydict[k]) except KeyError: pass I as well, but for other reasons (see below). But basically this is EAFP. (loads of them in many libraries and frameworks) instead of: if k in mydict: do_stuff(mydict[k]) This is LBYL, C-style, not Pythonic. I would do try: value = mydict[k] except KeyError: pass else: do_stuff(k) Why? Because do_stuff() might raise a KeyError, which should not go undetected. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: os.popen and the subprocess module
Am 27.11.2012 19:00 schrieb Andrew:
I'm looking into os.popen and the subprocess module, implementing
os.popen is easy but i hear it is depreciating however I'm finding the
implemantation of subprocess daunting can anyone help
This is only the first impression.
subprocess is much more powerful, but you don't need to use the full power.
For just executing and reading the data, you do not need much.
First step: create your object and performing the call:
sp = subprocess.Popen(['program', 'arg1', 'arg2'], stdout=subprocess.PIPE)
or
sp = subprocess.Popen('program arg1 arg2', shell=True,
stdout=subprocess.PIPE)
The variant with shell=True is more os.popen()-like, but has security
flaws (e.g., what happens if there are spaces or, even worse, ";"s in
the command string?
Second step: Obtain output.
Here you either can do
stdout, stderr = sp.communicate()
can be used if the whole output fits into memory at once or you really
have to deal with stderr or stdin additionally.
In other, simpler cases, it is possible to read from sp.stdout like from
a file (with a for loop, with .read() or whatever you like).
Third step: Getting the status, terminating the process.
And if you have read the whole output, you do status = sp.wait() in
order not to have a zombie process in your process table and to obtain
the process status.
Thomas
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Re: Python garbage collector/memory manager behaving strangely
Am 17.09.2012 04:28 schrieb Jadhav, Alok:
Thanks Dave for clean explanation. I clearly understand what is going on
now. I still need some suggestions from you on this.
There are 2 reasons why I was using self.rawfile.read().split('|\n')
instead of self.rawfile.readlines()
- As you have seen, the line separator is not '\n' but its '|\n'.
Sometimes the data itself has '\n' characters in the middle of the line
and only way to find true end of the line is that previous character
should be a bar '|'. I was not able specify end of line using
readlines() function, but I could do it using split() function.
(One hack would be to readlines and combine them until I find '|\n'. is
there a cleaner way to do this?)
- Reading whole file at once and processing line by line was must
faster. Though speed is not of very important issue here but I think the
tie it took to parse complete file was reduced to one third of original
time.
With
def itersep(f, sep='\0', buffering=1024, keepsep=True):
if keepsep:
keepsep=sep
else: keepsep=''
data = f.read(buffering)
next_line = data # empty? -> end.
while next_line: # -> data is empty as well.
lines = data.split(sep)
for line in lines[:-1]:
yield line+keepsep
next_line = f.read(buffering)
data = lines[-1] + next_line
# keepsep: only if we have something.
if (not keepsep) or data:
yield data
you can iterate over everything you want without needing too much
memory. Using a larger "buffering" might improve speed a little bit.
Thomas
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Re: how to simulate tar filename substitution across piped subprocess.Popen() calls?
Am 12.11.2012 19:30 schrieb Hans Mulder:
This will break if there are spaces in the file name, or other
characters meaningful to the shell. If you change if to
xargsproc.append("test -f '%s/{}'&& md5sum '%s/{}'"
% (mydir, mydir))
, then it will only break if there are single quotes in the file name.
And if you do mydir_q = mydir.replace("'", "'\\''") and use mydir_q, you
should be safe...
Thomas
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Re: how to simulate tar filename substitution across piped subprocess.Popen() calls?
Am 09.11.2012 02:12 schrieb Hans Mulder:
That's what 'xargs' will do for you. All you need to do, is invoke
xargs with arguments containing '{}'. I.e., something like:
cmd1 = ['tar', '-czvf', 'myfile.tgz', '-c', mydir, 'mysubdir']
first_process = subprocess.Popen(cmd1, stdout=subprocess.PIPE)
cmd2 = ['xargs', '-I', '{}', 'sh', '-c', "test -f %s/'{}'" % mydir]
second_process = subprocess.Popen(cmd2, stdin=first_process.stdout)
After launching second_process, it might be useful to
firstprocess.stdout.close(). If you fail to do so, your process is a
second reader which might break things apart.
At least, I once hat issues with it; I currently cannot recapitulate
what these were nor how they could arise; maybe there was just the open
file descriptor which annoyed me.
Thomas
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Re: stackoverflow quote on Python
Am 13.11.2012 14:21 schrieb wxjmfa...@gmail.com: * strings are now proper text strings (Unicode), not byte strings; Let me laugh. Do so. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Printing characters outside of the ASCII range
Am 09.11.2012 18:17 schrieb danielk: I'm using this character as a delimiter in my application. Then you probably use the *byte* 254 as opposed to the *character* 254. So it might be better to either switch to byte strings, or output the representation of the string instead of itself. So do print(repr(chr(254))) or, for byte strings, print(bytes([254])). Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Obnoxious postings from Google Groups
Am 31.10.2012 06:39 schrieb Robert Miles: For those of you running Linux: You may want to look into whether NoCeM is compatible with your newsreader and your version of Linux. This sounds as if it was intrinsically impossible to evaluate NoCeMs in Windows. If someone writes a software for it, it can be run wherever desired. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Immutability and Python
Am 29.10.2012 16:20 schrieb andrea crotti: Now on one hand I would love to use only immutable data in my code, but on the other hand I wonder if it makes so much sense in Python. You can have both. Many mutable types distinguish between them with their operators. To pick up your example, class NumWrapper(object): def __init__(self, number): self.number = number def __iadd__(self, x): self.number += x return self def __add__(self, x): return NumWrapper(self.number + x) So with number += 1 you keep the same object and modify it, while with number = number + 1 or new_number = number + 1 you create a new object. But more importantly normally classes are way more complicated than my stupid example, so recreating a new object with the modified state might be quite complex. Any comments about this? What do you prefer and why? That's why I generally prefer mutable objects, but it can depend. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: better way for ' '.join(args) + '\n'?
Am 26.10.2012 09:49 schrieb Ulrich Eckhardt:
Hi!
General advise when assembling strings is to not concatenate them
repeatedly but instead use string's join() function, because it avoids
repeated reallocations and is at least as expressive as any alternative.
What I have now is a case where I'm assembling lines of text for driving
a program with a commandline interface.
Stop.
In this case, you think too complicated.
Just do
subprocess.Popen(['prog', 'foo', 'bar', 'baz'])
- is the most safest thing for this use case.
If it should not be possible for any reason, you should be aware of any
traps you could catch - e.g., if you want to feed your string to a
Bourne shell, you should escape the strings properly.
In such cases, I use
def shellquote(*strs):
r"""Input: file names, output: ''-enclosed strings where every ' is
replaced with '\''. Intended for usage with the shell."""
# just take over everything except ';
# replace ' with '\''
# The shell sees ''' as ''\'''\'''\'''. Ugly, but works.
return " ".join([
"'"+st.replace("'","'\\''")+"'"
for st in strs
])
so I can use
shellquote('program name', 'argu"ment 1', '$arg 2',
"even args containing a ' are ok")
For Windows, you'll have to modify this somehow.
HTH,
Thomas
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Re: a.index(float('nan')) fails
Am 27.10.2012 06:48 schrieb Dennis Lee Bieber: I don't know about the more modern calculators, but at least up through my HP-41CX, HP calculators didn't do (binary) "floating point"... They did a form of BCD with a fixed number of significant /decimal/ digits Then, what about sqrt(x)**2 or arcsin(sin(x))? Did that always return the original x? Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: while expression feature proposal
Am 25.10.2012 18:36 schrieb Ian Kelly: On Thu, Oct 25, 2012 at 1:21 AM, Thomas Rachel wrote: j = next(j for j in iter(partial(randrange, n), None) if j not in selected) This generator never ends. If it meets a non-matching value, it just skips it and goes on. next() only returns one value. After it is returned, the generator is discarded, whether it has ended or not. If there were no valid values for randrange to select, then it would descend into an infinite loop. But then, so would the dropwhile and the original while loop. You are completely right. My solution was right as well, but didn't match the problem... Yours does indeed return one random value which is guaranteed not to be in selected. Mine returns random values until the value is not in selected. I just misread the intention behind the while loop... Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: while expression feature proposal
Am 25.10.2012 16:15 schrieb Grant Edwards: I guess that depends on what sort of programs you write. In my experience, EXPR is usually a read from a file/socket/pipe that returns '' on EOF. If VAR is not '', then you process, then you process it inside the loop. Right. The same as in if regex.search(string) as match: process it But with def if_true(expr): if expr: yield expr you can do for match in if_true(regex.search(string)): process it But the proposed if ... as ...: statment woulkd be more beautiful by far. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: while expression feature proposal
Am 25.10.2012 12:50 schrieb Steven D'Aprano: Then I think you have misunderstood the purpose of "yield from". Seems so. As I have not yet switched to 3.x, I haven't used it till now. [quote] However, if the subgenerator is to interact properly with the caller in the case of calls to send(), throw() and close(), things become considerably more difficult. As will be seen later, the necessary code is very complicated, and it is tricky to handle all the corner cases correctly. Ok, thanks. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: while expression feature proposal
Am 25.10.2012 09:21 schrieb Thomas Rachel: I think # iterate ad inf., because partial never returns None: i1 = iter(partial(randrange, n), None) # take the next value, make it None for breaking: i2 = (j if j in selected else None for j in i1) # and now, break on None: i3 = iter(lambda: next(i2), None) would do the job. But, as I read it now again, it might be cleaner to create an own generator function, such as def rand_values(randrange, n, selected): # maybe: selected = set(selected) for the "not in" while True: val = partial(randrange, n) if val not in selected: break yield val for value in rand_values(...): or, for the general case proposed some posings ago: def while_values(func, *a, **k): while True: val = func(*a, **k): if not val: break yield val Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: while expression feature proposal
Am 25.10.2012 06:50 schrieb Terry Reedy: Keep in mind that any new syntax has to be a substantial improvement in some sense or make something new possible. There was no new syntax in 3.2 and very little in 3.3. I would consinder this at least as new substantial than yield_from it as opposed to for i in it: yield i - although I think that was a good idea as well. Although there are quite easy ways to do so, I would appreciate something like the proposed while EXPR as VAR: use VAR if EXPR as VAR: use VAR Of course it is possible to construct a respective workaround such as def maybe_do_that(): if moon == full: with something as val: yield val for val in maybe_do_that(): bla but I would consider this as an abuse of the generator concept. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: while expression feature proposal
Am 25.10.2012 00:26 schrieb Cameron Simpson:
If I could write this as:
if re_FUNKYPATTERN.match(test_string) as m:
do stuff with the results of the match, using "m"
then some cascading parse decisions would feel a bit cleaner. Where I
current have this:
m = re_CONSTRUCT1.match(line)
if m:
... handle construct 1 ...
else:
m = re_CONSTRUCT2.match(line)
if m:
... handle construct 2 ...
else:
m = re_CONSTRUCT3.match(line)
I could have this:
if re_CONSTRUCT1.match(line) as m:
... handle construct 1 ...
elif re_CONSTRUCT2.match(line) as m:
... handle construct 2 ...
elif re_CONSTRUCT3.match(line) as m:
I would do
for r in re_CONSTRUCT1, re_CONSTRUCT2, re_CONSTRUCT3:
m = r.match(line)
if m: handle_construct
or maybe
actions = {re_CONSTRUCT1: action1, ...}
def matching(line, *rr):
for r in rr:
m = r.match(line)
if m: yield r; return
for r in matching(line, *actions.keys()):
actions[r]()
break
else:
raise NoActionMatched() # or something like that
Thomas
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Re: while expression feature proposal
Am 25.10.2012 01:39 schrieb Ian Kelly: On Wed, Oct 24, 2012 at 5:08 PM, Paul Rubin wrote: from itertools import dropwhile j = dropwhile(lambda j: j in selected, iter(lambda: int(random() * n), object())) .next() kind of ugly, makes me wish for a few more itertools primitives, but I think it expresses reasonably directly what you are trying to do. Nice, although a bit opaque. I think I prefer it as a generator expression: j = next(j for j in iter(partial(randrange, n), None) if j not in selected) This generator never ends. If it meets a non-matching value, it just skips it and goes on. The dropwhile expression, however, stops as soon as the value is found. I think # iterate ad inf., because partial never returns None: i1 = iter(partial(randrange, n), None) # take the next value, make it None for breaking: i2 = (j if j in selected else None for j in i1) # and now, break on None: i3 = iter(lambda: next(i2), None) would do the job. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Python does not take up available physical memory
Am 19.10.2012 21:03 schrieb Pradipto Banerjee: Thanks, I tried that. What is "that"? It would be helpful to quote in a reasonable way. Look how others do it. Still got MemoryError, but at least this time python tried to use the physical memory. What I noticed is that before it gave me the error it used up to 1.5GB (of the 2.23 GB originally showed as available) - so in general, python takes up more memory than the size of the file itself. Of course - the file is not the only thing to be held by the process. I see several approaches here: * Process the file part by part - as the others already suggested, line-wise, but if you have e.g. a binary file format, other partings may be suitable as well - e.g. fixed block size, or parts given by the file format. * If you absolutely have to keep the whole file data in memory, split it up in several strings. Why? Well, the free space in virtual memory is not necessarily contiguous. So even if you have 1.5G free, you might not be able to read 1.5G at once, but you might succeed in reading 3*0.5G. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: overriding equals operation
Am 16.10.2012 15:51 schrieb Pradipto Banerjee: I am trying to define class, where if I use a statement a = b, then instead of "a" pointing to the same instance as "b", it should point to a copy of "b", but I can't get it right. This is not possible. Currently, I have the following: class myclass(object): Myclass or MyClass, see http://www.python.org/dev/peps/pep-0008/. def __eq__(self, other): if instance(other, myclass): return self == other.copy() return NotImplemented This redefines the == operator, not the = operator. It is not possible to redefine =. One way could be to override assignment of a class attribute. But this won't be enough, I think. Let me explain: class MyContainer(object): @property def content(self): return self._content @content.setter def content(self, new): self._content = new.copy() Then you can do: a = MyClass() b = MyContainer() b.content = a print b.content is a # should print False; untested... But something like a = MyClass() b = a will always lead to "b is a". This communication is for informational purposes only. It is not intended to be, nor should it be construed or used as, financial, legal, tax or investment advice or an offer to sell, or a solicitation of any offer to buy, an interest in any fund advised by Ada Investment Management LP, the Investment advisor. What? Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: fastest data structure for retrieving objects identified by (x, y) tuple?
Am 04.10.2012 03:58 schrieb Steven D'Aprano: alist = [[None]*2400 for i in range(2400)] from random import randrange for i in range(1000): x = randrange(2400) y = randrange(2400) adict[(x, y)] = "something" alist[x][y] = "something" The actual sizes printed will depend on how sparse the matrices are, but for the same above (approximately half full), I wouldn't consider 1000 of 576 "half full"... Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: data attributes override method attributes?
Am 25.09.2012 16:08 schrieb Peter Otten: Jayden wrote: In the Python Tutorial, Section 9.4, it is said that "Data attributes override method attributes with the same name." The tutorial is wrong here. That should be "Instance attributes override class attributes with the same name." I jump in here: THere is one point to consider: if you work with descriptors, it makes a difference if they are "data descriptors" (define __set__ and/or __delete__) or "non-data descriptors" (define neither). As http://docs.python.org/reference/datamodel.html#invoking-descriptors tells us, methods are non-data descriptors, so they can be overridden by instances. OTOH, properties are data descriptors which cannot be overridden by the instance. So, to stick to the original example: class TestDesc(object): def a(self): pass @property def b(self): print "trying to get value - return None"; return None @b.setter def b(self, v): print "value", v, "ignored." @b.deleter def b(self): print "delete called and ignored" and now >>> t=TestDesc() >>> t.a > >>> t.b trying to get value - return None >>> t.a=12 >>> t.b=12 value 12 ignored. >>> t.a 12 >>> t.b trying to get value - return None >>> del t.a >>> del t.b delete called and ignored >>> t.a > >>> t.b trying to get value - return None Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: python file API
Am 25.09.2012 09:28 schrieb Steven D'Aprano: The whole concept is incomplete at one place: self.seek(10, 2) seeks beyond EOF, potentially creating a sparse file. This is a thing you cannot achieve. On the contrary, since the pos attribute is just a wrapper around seek, you can seek beyond EOF easily: f.pos = None f.pos += 10 Yes, from a syscall perspective, it is different: it is a tell() combined with a seek set instead of a relative seek. As someone mentionned, e. g. in the case of a streamer tape this might make a big difference. But for anything but the most trivial usage, I would recommend sticking to the seek method. ACK. This should be kept as a fallback. ... or we need multiple attributes, one for each mode ... Yes. That's what I would favourize: 3 attributes which each take a value to be passed to seek. So all up, I'm -1 on trying to replace the tell/seek API, and -0 on adding a second, redundant API. ACK. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: python file API
Am 25.09.2012 10:13 schrieb Dennis Lee Bieber: Or some bit setting registers, like on ATxmega: OUT = 0x10 sets bit 7 and clears all others, OUTSET = 0x10 only sets bit 7, OUTTGL = 0x10 toggles it and OUTCLR = 0x10 clears it. Umpfzg. s/bit 7/bit 4/. I don't think I'd want to work with any device where 0x10 (0001 binary) modifies bit SEVEN. 0x40, OTOH, would fit my mental impression of bit 7. Of course. My fault. It can as well be a bit mask, with OUTTGL = 0x11 toggling bit 4 and bit 0. Very handy sometimes. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: For Counter Variable
Am 25.09.2012 01:39 schrieb Dwight Hutto: It's not the simpler solution I'm referring to, it's the fact that if you're learning, then you should be able to design the built-in, not just use it. In some simpler cases you are right here. But the fact that you are able to design it doesn't necessarily mean that you should actually use your self-designed version. But what you post suggests is important as well: if using the neat fancy built-in simplifications, you should always be aware what overhead they imply. An example: Let l be a big, big list. for i in : if i in l: This looks neat and simple and doesn't look as expensive as it really is. If l is converted to a set beforehand, it nearly looks the same, but it is simpler. So even if you use builtins, be aware what they do. You don't always know all the built-ins, so the builtin is simpler, but knowing how to code it yourself is the priority of learning to code in a higher level language, which should be simpler to the user of python. When learning Python, it often happend me to re-inven the wheel. But as soon as I saw the presence of something I re-wrote, I skipped my re-written version and used the built-in. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: which a is used?
Am 25.09.2012 07:22 schrieb Dwight Hutto: No, not really. If you wanna talk shit, I can reflect that, and if you wanna talk politely I can reflect that. I go t attacked first., But not in this thread. Some people read only selectively and see only your verbal assaults, without noticing that they refer to. If you was really insulted, you should answer to these insults in their thread and not in a different one. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: python file API
Am 25.09.2012 00:37 schrieb Ian Kelly: On Mon, Sep 24, 2012 at 4:14 PM, Chris Angelico wrote: file.pos = 42 # Okay, you're at position 42 file.pos -= 10 # That should put you at position 32 foo = file.pos # Presumably foo is the integer 32 file.pos -= 100 # What should this do? Since ints are immutable, the language specifies that it should be the equivalent of "file.pos = file.pos - 100", so it should set the file pointer to 68 bytes before EOF. But this is not a "real int", it has a special use. So I don't think it is absolutely required to behave like an int. This reminds me of some special purpose registers in embedded programming, where bits can only be set by hardware and are cleared by the application by writing 1 to them. Or some bit setting registers, like on ATxmega: OUT = 0x10 sets bit 7 and clears all others, OUTSET = 0x10 only sets bit 7, OUTTGL = 0x10 toggles it and OUTCLR = 0x10 clears it. If this behaviour is documented properly enough, it is quite OK, IMHO. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: python file API
Am 25.09.2012 04:28 schrieb Steven D'Aprano: By the way, the implementation of this is probably trivial in Python 2.x. Untested: class MyFile(file): @property def pos(self): return self.tell() @pos.setter def pos(self, p): if p< 0: self.seek(p, 2) else: self.seek(p) You could even use a magic sentinel to mean "see to EOF", say, None. if p is None: self.seek(0, 2) although I don't know if I like that. The whole concept is incomplete at one place: self.seek(10, 2) seeks beyond EOF, potentially creating a sparse file. This is a thing you cannot achieve. But the idea is great. I'd suggest to have another property: [...] @pos.setter def pos(self, p): self.seek(p) @property def eofpos(self): # to be consistent return self.tell() @eofpos.setter def eofpos(self, p): self.seek(p, 2) Another option could be a special descriptor which can be used as well for relative seeking: class FilePositionDesc(object): def __init__(self): pass def __get__(self, instance, owner): return FilePosition(self) def __set__(self, value): self.seek(value) class FilePosition(object): def __init__(self, file): self.file = file def __iadd__(self, offset): self.file.seek(offset, 1) def __isub__(self, offset): self.file.seek(-offset, 1) class MyFile(file): pos = FilePositionDesc() [...] Stop. This could be handled with a property as well. Besides, this breaks some other expectations to the pos. So let's introduce a 3rd property named relpos: class FilePosition(object): def __init__(self, file): self.file = file self.seekoffset = 0 def __iadd__(self, offset): self.seekoffset += offset def __isub__(self, offset): self.seekoffset -= offset def __int__(self): return self.file.tell() + self.seekoffset class MyFile(file): @property def relpos(self): return FilePosition(self) # from above @relpos.setter def relpos(self, ofs): try: o = ofs.seekoffset # is it a FilePosition? except AttributeError: self.seek(ofs, 1) # no, but ofs can be an int as well else: self.seek(o, 1) # yes, it is Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: which a is used?
Am 25.09.2012 04:37 schrieb Dwight Hutto: I honestly could not care less what you think about me, but don't use that term. This isn't a boys' club and we don't need your hurt ego driving people away from here. OH. stirrin up shit and can't stand the smell. Where did he so? Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: which a is used?
Am 25.09.2012 03:47 schrieb Dwight Hutto: But within a class this is could be defined as self.x within the functions and changed, correct? class a(): def __init__(self,a): self.a = a def f(self): print self.a def g(self): self.a = 20 print self.a a = a(1) a.f() a.g() Yes - this is a different situation. Here, the "self" referred to is the same in all cases (the "a" from top level), and so self.a can be used consistently as well. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Using dict as object
Am 19.09.2012 12:24 schrieb Pierre Tardy: One thing that is cooler with java-script than in python is that dictionaries and objects are the same thing. It allows browsing of complex hierarchical data syntactically easy. For manipulating complex jsonable data, one will always prefer writing: buildrequest.properties.myprop rather than brdict['properties']['myprop'] This is quite easy to achieve (but not so easy to understand): class JsObject(dict): def __init__(self, *args, **kwargs): super(JsObject, self).__init__(*args, **kwargs) self.__dict__ = self (Google for JSObject; this is not my courtesy). What does it do? Well, an object's attributes are stored in a dict. If I subclass dict, the resulting class can be used for this as well. In this case, a subclass of a dict gets itself as its __dict__. What happens now is d = JsObject() d.a = 1 print d['a'] # This results in d.__dict__['a'] = 1. # As d.__dict__ is d, this is equivalent to d['a'] = 1. # Now the other way: d['b'] = 42 print d.b # here as well: d.b reads d.__dict__['b'], which is essentially d['b']. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: 'indent'ing Python in windows bat
Am 18.09.2012 15:03 schrieb David Smith:
I COULD break down each batch file and write dozens of mini python
scripts to be called. I already have a few, too. Efficiency? Speed is
bad, but these are bat files, after all. The cost of trying to work with
a multitude of small files is high, though, and I realized I had better
go to a mix.
In order to achieve this, it might be very useful to either have a
module for each (bigger) part to be achieved which you can call with
python -m modulename arg1 arg2 arg3
and putting the Python code into modulename.py.
Or you have one big "interpreter" which works this way:
class Cmd(object):
"""
Command collector
"""
def __init__(self):
self.cmds = {}
def cmd(self, f):
# register a function
self.cmds[f.__name__] = f
return f
def main(self):
import sys
sys.exit(self.cmds[sys.argv[1]](*sys.argv[2:]))
cmd = Cmd()
@cmd.cmd
def cmd1(arg1, arg2):
do_stuff()
...
return 1 # error -> exit()
@cmd.cmd
def cmd2():
...
if __name__ == '__main__':
cmd.main()
This is suitable for many small things and can be used this way:
bat cmds
python -m thismodule cmd1 a b
other bat cmds
python -m thismodule cmd2
...
HTH,
Thomas
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Re: Decorators not worth the effort
Am 15.09.2012 16:18 schrieb 8 Dihedral: The concept of decorators is just a mapping from a function ... or class ... > to another function ... or any other object ... > with the same name in python. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: using text file to get ip address from hostname
Am 15.09.2012 18:20 schrieb Dan Katorza:
hello again friends,
thanks for everyone help on this.
i guess i figured it out in two ways.
the second one i prefer the most.
i will appreciate if someone can give me some tips.
thanks again
so...
-
First
-
#!/usr/bin/env python
#Get the IP Address
print("hello, please enter file name here>"),
import socket
for line in open(raw_input()):
hostname = line.strip()
print("IP address for {0} is
{1}.".format(hostname,socket.gethostbyname(hostname)))
second
#!/usr/bin/env python
#Get the IP Address
import os
print("Hello, please enter file name here>"),
FILENAME = raw_input()
if os.path.isfile(FILENAME):
print("\nFile Exist!")
print("\nGetting ip from host name")
print("\n")
import socket
for line in open (FILENAME):
hostname = line.strip()
print("IP address for {0} is
{1}.".format(hostname,socket.gethostbyname(hostname)))
else:
print ("\nFinished the operation")
else:
print ("\nFIle is missing or is not reasable"),
~
Comparing these, the first one wins if you catch and process exceptions.
It is easier to ask for forgiveness than to get permission (EAFP,
http://en.wikipedia.org/wiki/EAFP).
Bit I wonder that no one has mentionned that
socket.gethostbyname(hostname) is quite old-age because it only returns
IPv4 addresses (resp. only one of them).
OTOH, socket.getaddrinfo(hostname, 0, 0, socket.SOCK_STREAM) gives you a
list of parameter tuples for connecting.
So which way you go above, you should change the respective lines to
for line in ...:
hostname = line.strip()
for target in socket.getaddrinfo(hostname, 0, socket.AF_UNSPEC,
socket.SOCK_STREAM):
print("IP address for {0} is {1}.".format(hostname,
target[4][0]))
Thomas
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Re: Decorators not worth the effort
[Sorry, my Firefox destroyed the indent...
Am 14.09.2012 22:29 schrieb Terry Reedy:
In other words
def make_wrapper(func, param):
def wrapper(*args, **kwds):
for i in range(param):
func(*args, **kwds)
return wrapper
def f(x): print(x)
f = make_wrapper(f, 2)
f('simple')
# is simpler, at least for some people, than the following
# which does essentially the same thing.
def make_outer(param):
def make_inner(func):
def wrapper(*args, **kwds):
for i in range(param):
func(*args, **kwds)
return wrapper
return make_inner
@make_outer(2)
def f(x): print(x)
f('complex')
For this case, my mydeco.py which I use quite often contains a
def indirdeco(ind):
# Update both the outer as well as the inner wrapper.
# If we knew the inner one was to be updated with something
# from *a, **k, we could do it. But not this way...
@functools.wraps(ind)
def outer(*a, **k):
@functools.wraps(ind)
def inner(f):
return ind(f, *a, **k)
return inner
return outer
so I can do
@indirdeco
def make_wrapper(func, param):
@functools.wraps(func)
def wrapper(*args, **kwds):
for i in range(param):
func(*args, **kwds)
return wrapper
and then nevertheless
@make_wrapper(2)
def f(x): print(x)
BTW, I also have a "meta-decorator" for the other direction:
def wrapfunction(mighty):
"""Wrap a function taking (f, *a, **k) and replace it with a
function taking (f) and returning a function taking (*a, **k) which
calls our decorated function.
Other direction than indirdeco."""
@functools.wraps(mighty)
def wrapped_outer(inner):
@functools.wraps(inner)
def wrapped_inner(*a, **k):
return mighty(inner, *a, **k)
wrapped_inner.func = inner # keep the wrapped function
wrapped_inner.wrapper = mighty # and the replacement
return wrapped_inner
wrapped_outer.func = mighty # keep this as well
return wrapped_outer
With this, a
@wrapfunction
def twice(func, *a, **k):
return func(*a, **k), func(*a, **k)
can be used with
@twice
def f(x): print (x); return x
very nicely.
Thomas
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Re: how to get os.py to use an ./ntpath.py instead of Lib/ntpath.py
Am 11.09.2012 05:46 schrieb Steven D'Aprano:
Good for you. (Sorry, that comes across as more condescending than it is
intended as.) Monkey-patching often gets used for quick scripts and tiny
pieces of code because it works.
Just beware that if you extend that technique to larger bodies of code,
say when using a large framework, or multiple libraries, your experience
may not be quite so good. Especially if *they* are monkey-patching too,
as some very large frameworks sometimes do. (Or so I am lead to believe.)
This sonds like a good use case for a context manager, like the one in
decimal.Context.get_manager().
First shot:
@contextlib.contextmanager
def changed_os_path(**k):
old = {}
try:
for i in k.items():
old[i] = getattr(os.path, i)
setattr(os.path, i, k[i])
yield None
finally:
for i in k.items():
setattr(os.path, i, old[i])
and so for your code you can use
print 'os.walk(\'goo\') with modified isdir()'
with changed_os_path(isdir=my_isdir):
for root, dirs, files in os.walk('goo'):
print root, dirs, files
so the change is only effective as long as you are in the relevant code
part and is reverted as soon as you leave it.
Thomas
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Re: generators as decorators simple issue
Am 12.09.2012 04:28 schrieb j.m.dagenh...@gmail.com: I'm trying to call SetName on an object to prevent me from ever having to call it explictly again on that object. Best explained by example. def setname(cls): '''this is the proposed generator to call SetName on the object''' try: cls.SetName(cls.__name__) finally: yield cls class Trial: '''class to demonstrate with''' def SetName(self, name): print 1, 1 @setname class Test(Trial): '''i want SetName to be called by using setname as a decorator''' def __init__(self): print 'Yay! or Invalid.' if __name__ == '__main__': test = Test() How can i fix this? I am not sure what exactly you want to achieve, but I see 2 problems here: 1. Your setname operates on a class, but your SetName() is an instance function. 2. I don't really understand the try...finally yield stuff. As others already said, you probably just want to return. I don't see what a generator would be useful for here... def setname(cls): '''this is the proposed generator to call SetName on the object''' try: cls.SetName(cls.__name__) finally: return cls and class Trial(object): '''class to demonstrate with''' @classmethod def SetName(cls, name): print 1, 1 should solve your problems. -- http://mail.python.org/mailman/listinfo/python-list
Re: set and dict iteration
Am 19.08.2012 00:14 schrieb MRAB: Can someone who is more familiar with the cycle detector and cycle breaker, help prove or disprove the above? In simple terms, when you create an immutable object it can contain only references to pre-existing objects, but in order to create a cycle you need to make an object refer to another which is created later, so it's not possible to create a cycle out of immutable objects. Yes, but if I add a list in-between, I can create a refcycle: a = [] b = (a,) a.append(b) So b is a tuple consisting of one list which in turn contains b. It is not a direct cycle, but an indirect one. Or would that be detected via the list? Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: On-topic: alternate Python implementations
Am 04.08.2012 11:10 schrieb Stefan Behnel: As long as you don't use any features of the Cython language, it's plain Python. That makes it a Python compiler in my eyes. Tell that the C++ guys. C++ is mainly a superset of C. But nevertheless, C and C++ are distinct languages and so are Python and Cython. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: What's wrong with this code?
Am 24.07.2012 09:47 schrieb Ulrich Eckhardt: [0] Note that in almost all cases, when referring to a tag, Python implicitly operates on the object attached to it. One case (the only one?) where it doesn't is the "del" statement. The del and the =, concerning the left side. But even those don't do that under all circumstances. Think about __setitem__, __setattr__, __set__, __delitem__, __delattr__, __delete__. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: the meaning of r`.......`
Am 23.07.2012 17:59 schrieb Steven D'Aprano: >> Before you get a language that uses full Unicode, you'll need to have fairly generally available keyboards that have those keys. Or at least keys or key combinations for the stuff you need, which might differ e. g. with the country you live in. There are countries which have keyboards with äöüÃ, others with èà éî, and so on. Or sensible, easy to remember mnemonics for additional characters. Back in 1984, Apple Macs made it trivial to enter useful non-ASCII characters from the keyboard. E.g.: Shift-4 gave $ Option-4 gave ¢ Option-c gave © Option-r gave ® So what? If I type Shift-3 here, I get a § (U+00A7). And the ° (U+00B0) comes with Shift-^, the µ (U+00B5) with AltGr-M and the ⬠sign with AltGr+E. Dead-keys made accented characters easy too: Option-u o gave ö Option-u e gave ë And if I had a useful OS here at work, I even could use the compose key to produce many other non-ASCII characters. To be able to create each and every of them is not needed in order to have support for them in a language, just the needed ones. Useful editors use them as well, although you have not all of them on your keyboard. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: What's wrong with this code?
Am 23.07.2012 16:50 schrieb Stone Li: I'm totally confused by this code: Code: a = None b = None c = None d = None x = [[a,b], [c,d]] e,f = x[1] print e,f c = 1 d = 2 print e,f e = 1 f = 2 print c,d Output: None None None None 1 2 I'm expecting the code as: None None 1 2 1 2 What's wrong? Your expectation :-) With c = 1 and d = 2 you do not change the respective objects, but you assign other objects to the same names. The old content is still contained in x[1]. If you would only modify these objects (not possible as ints are immutable), you would notice the changes here and there. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Generator vs functools.partial?
Am 21.06.2012 13:25 schrieb John O'Hagan: But what about a generator? Yes, but... def some_func(): arg = big_calculation() while 1: i = yield (do_something with arg and i) some_gen = some_func() some_gen.send(None) for i in lots_of_items: some_gen.send(i) rather def some_func(it): arg = big_calculation() for i in it: do_something(arg, i) some_func(lots_of_items) HTH, Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Is that safe to use ramdom.random() for key to encrypt?
Am 18.06.2012 01:48 schrieb Paul Rubin: Steven D'Aprano writes: /dev/urandom isn't actually cryptographically secure; it promises not to block, even if it has insufficient entropy. But in your instance... Correct. /dev/random is meant to be used for long-lasting cryptographically-significant uses, such as keys. urandom is not. They are both ill-advised if you're doing anything really serious. Hm? > In practice if enough entropy has been in the system to make a key with /dev/random, then urandom should also be ok. Right. > Unfortunately the sensible interface is missing: block until there's enough entropy, then generate data cryptographically, folding in new entropy when it's available. What am I missing? You exactly describe /dev/random's interface. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: post init call
Am 18.06.2012 09:10 schrieb Prashant: class Shape(object): def __init__(self, shapename): self.shapename = shapename def update(self): print "update" class ColoredShape(Shape): def __init__(self, color): Shape.__init__(self, color) self.color = color print 1 print 2 print 3 self.update() User can sub-class 'Shape' and create custom shapes. How ever user must call 'self.update()' as the last argument when ever he is sub-classing 'Shape'. I would like to know if it's possible to call 'self.update()' automatically after the __init__ of sub-class is done? Cheers I would construct it this way: class Shape(object): def __init__(self, *args): self.args = args self.init() self.update() # or: if self.init(): self.update() def init(self): return False # don't call update def update(self): print "update" @propery def shapename(self): return self.args[0] class ColoredShape(Shape): def init(self): print 1, 2, 3 self.update() return True @property def color(self): return self.args[1] Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: python3 raw strings and \u escapes
Am 30.05.2012 08:52 schrieb ru...@yahoo.com: This breaks a lot of my code because in python 2 re.split (ur'[\u3000]', u'A\u3000A') ==> [u'A', u'A'] but in python 3 (the result of running 2to3), re.split (r'[\u3000]', 'A\u3000A' ) ==> ['A\u3000A'] I can remove the "r" prefix from the regex string but then if I have other regex backslash symbols in it, I have to double all the other backslashes -- the very thing that the r-prefix was invented to avoid. Or I can leave the "r" prefix and replace something like r'[ \u3000]' with r'[ ]'. But that is confusing because one can't distinguish between the space character and the ideographic space character. It also a problem if a reader of the code doesn't have a font that can display the character. Was there a reason for dropping the lexical processing of \u escapes in strings in python3 (other than to add another annoyance in a long list of python3 annoyances?) Probably it is more consequent. Alas, it makes the whole stuff incompatible to Py2. But if you think about it: why allow for \u if \r, \n etc. are disallowed as well? And is there no choice for me but to choose between the two poor choices I mention above to deal with this problem? There is a 3rd one: use r'[ ' + '\u3000' + ']'. Not very nice to read, but should do the trick... Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: why () is () and [] is [] work in other way?
Am 24.04.2012 15:25 schrieb rusi: Identity, sameness, equality and the verb to be are all about the same concept(s) and their definitions are *intrinsically* circular; see http://plato.stanford.edu/entries/identity/#2 Mybe in real life language. In programming and mathematics there are several forms of equality, where identity (≡) is stronger than equality (=). Two objects can be equal (=) without being identical (≡), but not the other way. As the ≡ is quite hard to type, programming languages tend to use other operators for this. E.g., in C, you can have int a; int b; a = 4; b = 4; Here a and b are equal, but not identical. One can be changed without changing the other. With int x; int *a=&x, *b=&x; *a and *b are identical, as they point to the same location. *a = 4 results in *b becoming 4 as well. In Python, you can have the situations described here as well. You can have a list and bind it to 2 names, or you can take 2 lists and bind them to that name. a = [3] b = [3] Here a == b is True, while a is b results in False. Thomas And the seeming simplicity of the circular definitions hide the actual complexity of 'to be' for python: http://docs.python.org/reference/expressions.html#id26 (footnote 7) for math/philosophy: http://www.math.harvard.edu/~mazur/preprints/when_is_one.pdf -- http://mail.python.org/mailman/listinfo/python-list
Re: why () is () and [] is [] work in other way?
Am 24.04.2012 08:02 schrieb rusi: On Apr 23, 9:34 am, Steven D'Aprano wrote: "is" is never ill-defined. "is" always, without exception, returns True if the two operands are the same object, and False if they are not. This is literally the simplest operator in Python. Circular definition: In case you did not notice, 'is' and 'are' are (or is it is?) the same verb. Steven's definition tries not to define the "verb" "is", but it defines the meanung of the *operator* 'is'. He says that 'a is b' iff a and be are *the same objects*. We don't need to define the verb "to be", but the target of the definition is the entity "object" and its identity. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: python module
Am 16.04.2012 12:23 schrieb Kiuhnm: I'd like to share a module of mine with the Python community. I'd like to encourage bug reports, suggestions, etc... Where should I upload it to? Kiuhnm There are several ways to do this. One of them would be bitbucket. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: ordering with duck typing in 3.1
Am 07.04.2012 14:23 schrieb andrew cooke: class IntVar(object): def __init__(self, value=None): if value is not None: value = int(value) self.value = value def setter(self): def wrapper(stream_in, thunk): self.value = thunk() return self.value return wrapper def __int__(self): return self.value def __lt__(self, other): return self.value< other def __eq__(self, other): return self.value == other def __hash__(self): return hash(self.value) so what am i missing? If I don't confuse things, I think you are missing a __gt__() in your IntVar() class. This is because first, a '2 < three' is tried with 2.__lt__(three). As this fails due to the used types, it is reversed: 'three > 2' is equivalent. As your three doesn't have a __gt__(), three.__gt__(2) fails as well. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: No os.copy()? Why not?
Am 03.04.2012 11:34 schrieb John Ladasky: I use subprocess.call() for quite a few other things. I just figured that I should use the tidier modules whenever I can. Of course. I only wanted to point out that os.system() is an even worse approach. shutils.copy() is by far better, of course. -- http://mail.python.org/mailman/listinfo/python-list
