Carl Banks wrote:
Here's another reason not to use if lst. Say you have a function
that looks like this:
def process_values(lst):
if not lst:
return
do_expensive_initialization_step()
for item in lst:
do_something_with(item)
Daniel Dittmar wrote:
Premature generalization: the new 'premature optimization'.
Premature specialization: the new 'static typing'.
-- Pat
--
http://mail.python.org/mailman/listinfo/python-list
PTY wrote:
It looks like there are two crowds, terse and verbose. I thought terse
is perl style and verbose is python style. BTW, lst = [] was not what
I was interested in :-) I was asking whether it was better style to
use len() or not.
It's not canonical Python to use len() in this
Duncan Booth wrote:
I prefer writing an 'if' statement here, Bryan prefers 'get', that's just a
choice of style. But 'setdefault' here, that has no style.
Well, I'm often told I have no style, and I _did_ admit that it's an
abuse of setdefault. However, I often use setdefault to populate
Duncan Booth showed how to solve a problem posed by Mathijs. This is
very similar to Duncan's solution, except I (ab)use setdefault on a
regular basis...
def occurrences(t):
... res = {}
... for item in t:
... res.setdefault(item,[0])[0] += 1
... return res
...
ref =
Mike Meyer wrote:
This is where we disagree. I think their understanding of references
is dead on. What's broken is their understanding of what variables are
and what assignments mean. Once you fix that, the rest falls into
place.
(Steven D'Aprano wrote:)
The fact that call by object is
Mike Meyer wrote:
This is where we disagree. I think their understanding of references
is dead on. What's broken is their understanding of what variables are
and what assignments mean. Once you fix that, the rest falls into
place.
(Steven D'Aprano wrote:)
The fact that call by object is
Mike Meyer wrote:
This is where we disagree. I think their understanding of references
is dead on. What's broken is their understanding of what variables are
and what assignments mean. Once you fix that, the rest falls into
place.
(Steven D'Aprano wrote:)
The fact that call by object is
Mike Meyer wrote:
This is where we disagree. I think their understanding of references
is dead on. What's broken is their understanding of what variables are
and what assignments mean. Once you fix that, the rest falls into
place.
(Steven D'Aprano wrote:)
The fact that call by object is
Alec Wysoker wrote:
Using Python 2.3.5 on Windows XP, I occasionally get OSError:
[Errno 13] Permission denied when calling os.remove(). This can
occur with a file that is not used by any other process on the
machine, and is created by the python.exe invocation that is
trying to delete it.
Tim Peters wrote:
In that case, anything that burns some time and tries again
will work better. Replacing gc.collect() with time.sleep() is
an easy way to test that hypothesis; because gc.collect()
does an all-generations collection, it can consume measurable time.
An slight enhancement
for (i = nPoints-1, j = 0; j nPoints; i = j, j++)
A simple translation of this would be:
i = npoints-1
for j in range(npoints):
... (your code here)
i = j
HTH,
Pat
--
http://mail.python.org/mailman/listinfo/python-list
for (i = nPoints-1, j = 0; j nPoints; i = j, j++)
Alternatively, if you don't like the initial setup of i and would
prefer your setup code at the top of the loop:
for j in range(npoints):
i = (j-1) % npoints
... (your code here)
Finally, you could always do something like this:
Mike Meyer wrote:
. Note that I'm *not* interpreting the GPL. I'm interpreting what the
FSF says about the GPL. If the goal is to avoid a lawsuit, the latter
is what you have to pay attention to, as they're telling you what
actions you can take without getting sued. The text comes into play
Mike Meyer wrote:
. Note that I'm *not* interpreting the GPL. I'm interpreting what the
FSF says about the GPL. If the goal is to avoid a lawsuit, the latter
is what you have to pay attention to, as they're telling you what
actions you can take without getting sued. The text comes into play
Mike Meyer wrote:
. Note that I'm *not* interpreting the GPL. I'm interpreting what the
FSF says about the GPL. If the goal is to avoid a lawsuit, the latter
is what you have to pay attention to, as they're telling you what
actions you can take without getting sued. The text comes into play
Peter Hansen wrote:
Though, without knowing what the body does, one can't be sure
that's going to be a faithful translation. The for loop in Python
always iterates over the entire set of items given to it, unless
it's told to break early. But if j or nPoints is modified in the
body of the
Lunchtimemama wrote:
What is the superior method of exception handling:
...
For a start, note that the exception hook does not _really_ have to be
in the main module, just imported before any protected code is to be
executed.
Having said that, what I personally typically do for exception
Lunchtimemama wrote:
Yo all, I'm getting into Python for the first time and I'm really
having a blast. I've hit a bit of a snag and was wondering if someone
could lend some insight. Here be the code:
import sys
def myexcepthook(type, value, tb):
import traceback
rawreport =
Lunchtimemama wrote:
Forgive my ignorance, but I'm not quite sure what you mean. I tried
importing the traceback module at the beginning of the script, but that
didn't make a difference. Could you provide example code to illustrate
your comment? Thanks.
Assume your main module has your
MackS wrote:
print inside fun(): + global_var
...
How can I get the changed value to persist in such a way that it
isn't reset when control leaves fun()? Why is it even reset in the
first place? After all, the module has already been imported (and the
initialization of global_var
Ron Adam wrote:
This should never fail with an assertion error. You will note that it
shows that, for non-negative start and end values, slicing behavior is
_exactly_ like extended range behavior.
Yes, and it passes for negative start and end values as well.
Umm, no:
. for stride in [-3,
Sybren Stuvel wrote:
A programming language should not be ambiguous. The choice
between importing a module and calling a function should not
depend on the availability of a (local) variable.
Yeah, this behavior would be as ambiguous as if we had a system-defined
search-path for modules, where
No one has yet explained the reasoning (vs the mechanics) of the
returned value of the following.
L = range(10)
L[3::-1]
So far every attempt to explain it has either quoted the documents which
don't address that particular case, or assumed I'm misunderstanding
something, or
I previously wrote (in response to a query from Ron Adam):
In any case, you asked for a rationale. I'll give you mine:
L = range(10)
L[3:len(L):-1] == [L[i] for i in range(3,len(L),-1)]
True
After eating supper, I just realized that I could probably make my
point a bit clearer with a
After considering several alternatives and trying out a few ideas with a
modified list object Bengt Richter posted, (Thank You), I think I've
found a way to make slice operation (especially far end indexing)
symmetrical and more consistent.
I don't know that it makes it more consistent. I
Thomas wrote:
TURN $6 INTO $15,000 IN ONLY 30 DAYS...HERES HOW!
$ REMEMBER, IT IS 100% LEGAL! DON'T PASS THIS UP!
and I thought this was about some new currency/decimal module
implementation which remembers units and does the conversion
correctly...
--
John Roth wrote:
I'd like to suggest a different mechanism, at least for packages
(top level scripts don't generate .pyc files anyway.) Put a system
variable in the __init__.py file. Something like __obj__ = path
would do nicely. Then when Python created the __init__.pyc file,
it would
Jarek Zgoda wrote:
Why want you to read an XML document by hand? It's a machine related
data chunk.
I see this attitude all the time, and frankly I don't understand it.
Please explain why XML is in ASCII/unicode instead of binary. Is it
because it is easier for a machine to parse? No, I
Dennis Bieber wrote:
Off hand, I'd consider the non-binary nature to be because the
internet protocols are mostly designed for text, not binary.
A document at http://www.w3.org/TR/REC-xml/ lists the design goals for
XML.
One of the listed goals is XML documents should be human-legible and
Skip Montanaro wrote:
I wrote PEP 304, Controlling Generation of Bytecode Files:
...
If someone out there is interested in this functionality
and would benefit more from its incorporation into the
core, I'd be happy to hand it off to you.
I am quite interested in this PEP.
What, exactly,
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