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Selecting pandas column by location
... mind:
>>> df
A B C D
0 0.424634 1.716633 0.282734 2.086944
1 -1.325816 2.056277 2.583704 -0.776403
2 1.457809 -0.407279 -1.560583 -1.316246
3 -0.757134 -1.321025 1.325853 -2.513373
4 1.366180 -1.265185 -2.184617 0.881514
>>> df.iloc[:, ...
Return two and more values from a method
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def sumdiff(x, y)
return x+y, x-y
end
#=> nil
sumdiff(3, 4)
#=> [7, -1]
a = sumdiff(3,4)
#=> [7, -1]
a
#=> [7, -1]
a,b=sumdiff(3,4)
#=> [7, -1]
a
#=> 7
b
#=> -1
a,b,c=sumdiff(3,4)
#=> [7, -1]
a
#=> 7
b
#=> -1
c
#=> nil
...
Joda-Time: what's the difference between Period, Interval and Duration?
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3 classes are needed because they represent different concepts so it is a matter of picking the appropriate one for the job rather than of relative performance. From the documentation with comments added by me in italics:
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Regex to remove all (non numeric OR period)
I need for text like "joe ($3,004.50)" to be filtered down to 3004.50 but am terrible at regex and can't find a suitable solution. So only numbers and periods should stay - everything else filtered. I use C# and VS.net 2008 framework 3.5
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range over interface{} which stores a slice
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3 Answers
3
Active
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Cost of len() function
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360
It's O(1) (constant time, not depending of actual length of the element - very fast) on every ...
Optional Parameters with C++ Macros
...S(message, size) PrintString(message, size, 0)
#define PRINT_STRING_3_ARGS(message, size, style) PrintString(message, size, style)
#define GET_4TH_ARG(arg1, arg2, arg3, arg4, ...) arg4
#define PRINT_STRING_MACRO_CHOOSER(...) \
GET_4TH_ARG(__VA_ARGS__, PRINT_STRING_3_ARGS, \
...
How do you get the magnitude of a vector in Numpy?
...ray -- say x.norm() -- but oh well).
import numpy as np
x = np.array([1,2,3,4,5])
np.linalg.norm(x)
You can also feed in an optional ord for the nth order norm you want. Say you wanted the 1-norm:
np.linalg.norm(x,ord=1)
And so on.
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