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Apply a function to every row of a matrix or a data frame
..., byrow=TRUE)
R> M
[,1] [,2]
[1,] 1 2
[2,] 3 4
[3,] 5 6
R> apply(M, 1, function(x) 2*x[1]+x[2])
[1] 4 10 16
R>
This takes a matrix and applies a (silly) function to each row. You pass extra arguments to the function as fourth, fifth, ... arguments to apply().
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python pandas remove duplicate columns
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Jean-François Corbett
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answered Nov 5 '16 at 6:15
Gene BurinskyGene ...
How to compare strings ignoring the case
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5 Answers
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What does the constant 0.0039215689 represent?
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0.0039215689 is approximately equal to 1/255.
Seeing that this is OpenGL, performance is probably important. So it's probably safe to guess that this was done for performance reasons.
Multiplying by the reciprocal is faster than re...
How to get the first column of a pandas DataFrame as a Series?
...pandas as pd
>>> df = pd.DataFrame({'x' : [1, 2, 3, 4], 'y' : [4, 5, 6, 7]})
>>> df
x y
0 1 4
1 2 5
2 3 6
3 4 7
>>> s = df.ix[:,0]
>>> type(s)
<class 'pandas.core.series.Series'>
>>>
====================================================...
What does numpy.random.seed(0) do?
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598
np.random.seed(0) makes the random numbers predictable
>>> numpy.random.seed(0) ; nu...
Selecting data frame rows based on partial string match in a column
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150
I notice that you mention a function %like% in your current approach. I don't know if that's a ...
Most efficient way to create a zero filled JavaScript array?
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582
ES6 introduces Array.prototype.fill. It can be used like this:
new Array(len).fill(0);
Not ...