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How to use a custom comparison function in Python 3?
...e a workaround, but I think I am going to lose some performance by passing all the comparison operators < > = to middle man, since my original custom sort is written in C , it had around 1/2x speed of default sort.
– YOU
Mar 28 '10 at 5:26
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Numpy: find first index of value fast
...ments it. If you use anaconda python distribution it should already be installed.
The code will be compiled so it will be fast.
@jit(nopython=True)
def find_first(item, vec):
"""return the index of the first occurence of item in vec"""
for i in xrange(len(vec)):
if item == vec[i]:
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How to update Python?
I have version 2.7 installed from early 2012. I can't find any consensus on whether I should completely uninstall and wipe this version before putting on the latest version.
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What do the python file extensions, .pyc .pyd .pyo stand for?
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.py: This is normally the input source code that you've written.
.pyc: This is the compiled bytecode. If you import a module, python will build a *.pyc file that contains the bytecode to make importing it again later easier (and faster).
.pyo...
Why doesn't GCC optimize a*a*a*a*a*a to (a*a*a)*(a*a*a)?
...scientific application. One thing I noticed is that GCC will optimize the call pow(a,2) by compiling it into a*a , but the call pow(a,6) is not optimized and will actually call the library function pow , which greatly slows down the performance. (In contrast, Intel C++ Compiler , executable ...
In pure functional languages, is there an algorithm to get the inverse function?
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In some cases, yes! There's a beautiful paper called Bidirectionalization for Free! which discusses a few cases -- when your function is sufficiently polymorphic -- where it is possible, completely automatically to derive an inverse function. (It also discusses what makes...
nonlocal keyword in Python 2.x
...nswer by Elias Zamaria, but contrary to that answer does handle multiple calls of the outer function correctly. The "variable" inner.y is local to the current call of outer. Only it isn't a variable, since that is forbidden, but an object attribute (the object being the function inner itself). This...
Python Pandas: Get index of rows which column matches certain value
... frame (whose data may be gibabytes). What about dftest? Doesn't this also allocate a very large intermediate object where the returned index may be very small, or even empty. Are these magically optimized away using lazy views. If not then surely there must be an efficient way.
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Fastest method to replace all instances of a character in a string [duplicate]
What is the fastest way to replace all instances of a string/character in a string in JavaScript? A while , a for -loop, a regular expression?
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Exif manipulation library for python [closed]
...mation from Jpeg and Tiff files which include it. This information is typically included in images created using digital imaging devices such as digital cameras, digital film scanners, etc.
However, it looks like pyexif hasn't been updated in quite while. They recommend if theirs isn't doing the ...