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Can someone explain the traverse function in Haskell?
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traverse is the same as fmap, except that it also allows you to run effects while you're rebuilding the data structure.
Take a look at the example from the Data.Traversable documentation.
data Tree a = Empty | Leaf a | Node (Tree a) a (Tree a)
The Functor instance of Tr...
Standard way to embed version into python package?
...is also used in lots of 3rd-party modules, so it's the quasi-standard.
Usually, __version__ is a string, but sometimes it's also a float or tuple.
Edit: as mentioned by S.Lott (Thank you!), PEP 8 says it explicitly:
Module Level Dunder Names
Module level "dunders" (i.e. names with two lea...
How does this JavaScript/jQuery syntax work: (function( window, undefined ) { })(window)?
...d = "new value";. So jQuery creates a local "undefined" variable that is REALLY undefined.
The window variable is made local for performance reasons. Because when JavaScript looks up a variable, it first goes through the local variables until it finds the variable name. When it's not found, JavaScr...
How to commit my current changes to a different branch in Git [duplicate]
...nges should be committed in a branch different to the current one. This usually happens when I want to try out new things or do some testing and I forget to create a new branch beforehand, but I don't want to commit dirty code to the master branch.
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Is it feasible to compile Python to machine code?
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There are several options:
Use Psyco, which emits machine code dynamically. You should choose carefully which methods/functions to convert, though.
Use Cython, which is a Python-like language that is compiled into a Python C extension
Use PyPy, which has a translator from RPython (a restricted ...
How to debug a referenced dll (having pdb)
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I actually was able to debug a (release-)assembly today that was added as a file reference. Good for me, but how did that happen? MSVC2010, C#, (ASP).NET 4.0, referenced assembly exists as debug+release (but only release-file added...
The apk must be signed with the same certificates as the previous version
I had uploaded my app to Google Play (back when it was called Android Market) some time ago.
11 Answers
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What does if __name__ == “__main__”: do?
...ngs:
it sets a few special variables like __name__, and then
it executes all of the code found in the file.
Let's see how this works and how it relates to your question about the __name__ checks we always see in Python scripts.
Code Sample
Let's use a slightly different code sample to explore ho...
jQuery .ready in a dynamically inserted iframe
We are using jQuery thickbox to dynamically display an iframe when someone clicks on a picture. In this iframe, we are using galleria a javascript library to display multiple pictures.
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How do you append to a file in Python?
...n C++. If you forget close(), it might take a while before the file is actually closed. It is easier that you might think to forget it when the code has multiple exit points, exceptions and so on.
– Petter
Jun 13 '13 at 17:37
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