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When is memoization automatic in GHC Haskell?
... in foldl' (+) 0 (y ++ [x])
GHC might notice that y does not depend on x and rewrite the function to
f = let y = [1..30000000] in \x -> foldl' (+) 0 (y ++ [x])
In this case, the new version is much less efficient because it will have to read about 1 GB from memory where y is stored, while th...
Last non-empty cell in a column
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This works with both text and numbers and doesn't care if there are blank cells, i.e., it will return the last non-blank cell.
It needs to be array-entered, meaning that you press Ctrl-Shift-Enter after you type or paste it in. The below is for colu...
How to install packages offline?
What's the best way to download a python package and it's dependencies from pypi for offline installation on another machine? Is there any easy way to do this with pip or easy_install? I'm trying to install the requests library on a FreeBSD box that is not connected to the internet.
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How to deal with SettingWithCopyWarning in Pandas?
I just upgraded my Pandas from 0.11 to 0.13.0rc1. Now, the application is popping out many new warnings. One of them like this:
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What is the difference between shallow copy, deepcopy and normal assignment operation?
...wards the existing object. The docs explain the difference between shallow and deep copies:
The difference between shallow and deep copying is only relevant for
compound objects (objects that contain other objects, like lists or
class instances):
A shallow copy constructs a new compo...
Null vs. False vs. 0 in PHP
...m told that good developers can spot/utilize the difference between Null and False and 0 and all the other good "nothing" entities.
What is the difference, specifically in PHP? Does it have something to do with === ?
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jQuery's jquery-1.10.2.min.map is triggering a 404 (Not Found)
...get the files
Next, it's an easy fix. Head to http://jquery.com/download/ and click the Download the map file link for your version, and you'll want the uncompressed file downloaded as well.
Having the map file in place allows you do debug your minified jQuery via the original sources, which wil...
Which is the fastest algorithm to find prime numbers?
...ly I don't think primegen is the fastest, or even the second-fastest; yafu and primesieve are both faster in general, I think, and certainly over 2^32. Both are (modified) sieves of Eratosthenes rather than the Atkin-Bernstein sieve.
– Charles
Aug 19 '11 at 4:...
What is a lambda expression in C++11?
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The problem
C++ includes useful generic functions like std::for_each and std::transform, which can be very handy. Unfortunately they can also be quite cumbersome to use, particularly if the functor you would like to apply is unique to the particular function.
#include <algorithm>
#inclu...
Difference between == and ===
In swift there seem to be two equality operators: the double equals ( == ) and the triple equals ( === ), what is the difference between the two?
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