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Fastest way to replace NAs in a large data.table
... data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
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how to draw smooth curve through N points using javascript HTML5 canvas?
...nts), but for my purposes (a drawing application), it's good enough for me and visually you can't tell the difference. There is a solution to go through all the sample points, but it is much more complicated (see http://www.cartogrammar.com/blog/actionscript-curves-update/)
Here is the the drawing...
Better way to shuffle two numpy arrays in unison
...o sequences of the same length results in the same number of calls to the random number generator, and these are the only "random" elements in the shuffle algorithm. By resetting the state, you ensure that the calls to the random number generator will give the same results in the second call to shu...
bool operator ++ and --
... supports ++ (increment) for bool, but not -- (decrement). It this just a random decision, or there is some reason behind this?
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How does the bitwise complement operator (~ tilde) work?
...representation of a number, taking its complement (inverting all the bits) and adding one. Two starts as 0000 0010, and by inverting the bits we get 1111 1101. Adding one gets us the result above. The first bit is the sign bit, implying a negative.
So let's take a look at how we get ~2 = -3:
Here's ...
Chrome's remote debugging (USB debugging) not working for Samsung Galaxy S3 running android 4.3
Ever since I upgraded my Samsung Galaxy S3 to android 4.3 (from 4.1.2) I am unable to use Chrome's remote debugging for android (more details here ).
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how to use “AND”, “OR” for RewriteCond on Apache?
Is this how to use AND, OR for RewriteCond on Apache?
3 Answers
3
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List of lists changes reflected across sublists unexpectedly
...(3)]
which will reevaluate [1]*4 each time instead of evaluating it once and making 3 references to 1 list.
You might wonder why * can't make independent objects the way the list comprehension does. That's because the multiplication operator * operates on objects, without seeing expressions. Wh...
Accessing dict keys like an attribute?
... Unless - of course - you assign some value to them, see below)
Attributes and items are always in sync
Trying to access non-existent key as an attribute correctly raises AttributeError instead of KeyError
Supports [Tab] autocompletion (e.g. in jupyter & ipython)
Cons:
Methods like .keys() wil...
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...