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Why does the expression 0 < 0 == 0 return False in Python?
...o say 0 < x <= 5 than to say (0 < x) and (x <= 5).
These are called chained comparisons. And that's a link to the documentation for them.
With the other cases you talk about, the parenthesis force one relational operator to be applied before the other, and so they are no longer chained...
How do I check OS with a preprocessor directive?
...Unix (Linux, *BSD, Mac OS X)
See this related question on some of the pitfalls of using this check.
unix
__unix
__unix__
Mac OS X
__APPLE__
__MACH__
Both are defined; checking for either should work.
Linux
__linux__
linux Obsolete (not POSIX compliant)
__linux Obsolete (not POSIX compliant)
...
Getting the class name of an instance?
...note that the above method works with new-style classes only (in Python 3+ all classes are "new-style" classes). Your code might use some old-style classes. The following works for both:
x.__class__.__name__
share
...
Python: reload component Y imported with 'from X import Y'?
... verse (import this from interactive prompt to see the Zen of Python); and all the reasons why namespaces are a honking great idea (immediate local visual clues that the name's being looked up, ease of mocking/injecting in tests, ability to reload, ability for a module to change flexibly by redefini...
Multiple variables in a 'with' statement?
...textlib.nested, this guarantees that a and b will have their __exit__()'s called even if C() or it's __enter__() method raises an exception.
You can also use earlier variables in later definitions (h/t Ahmad below):
with A() as a, B(a) as b, C(a, b) as c:
doSomething(a, c)
...
Why is it slower to iterate over a small string than a small list?
...nd with timeit and noticed that doing a simple list comprehension over a small string took longer than doing the same operation on a list of small single character strings. Any explanation? It's almost 1.35 times as much time.
...
Ignore python multiple return value
...add gettext functionality to someone else's code (that defines a function called '_') so it should be banned
– nosklo
Jan 11 '09 at 13:32
28
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Determine if 2 lists have the same elements, regardless of order? [duplicate]
... helper function. Note that it will be quite slow (O(n²)) and should generally not be used outside of the esoteric case of unhashable and unsortable elements.
def equal_ignore_order(a, b):
""" Use only when elements are neither hashable nor sortable! """
unmatched = list(b)
for element...
What to put in a python module docstring? [closed]
...ngs; the module's own docstring should describe them very summarily (if at all) and rather concentrate on a concise summary of what the module as a whole can do for you, ideally with some doctested examples (just like functions and classes ideally should have doctested examples in their docstrings)....
How do I check if a string is a number (float)?
...r.
I'm not sure that anything much could be faster than the above. It calls the function and returns. Try/Catch doesn't introduce much overhead because the most common exception is caught without an extensive search of stack frames.
The issue is that any numeric conversion function has two kin...