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How to assign from a function which returns more than one value?
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13 Answers
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Normalize data in pandas
...In [92]: df
Out[92]:
a b c d
A -0.488816 0.863769 4.325608 -4.721202
B -11.937097 2.993993 -12.916784 -1.086236
C -5.569493 4.672679 -2.168464 -9.315900
D 8.892368 0.932785 4.535396 0.598124
In [93]: df_norm = (df - df.mean()) / (df.max() - df.min()...
What is /dev/null 2>&1?
... the same net effect. I usually just use > for that reason.)
2>&1 redirects standard error (2) to standard output (1), which then discards it as well since standard output has already been redirected.
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Apply pandas function to column to create multiple new columns?
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Sorting multiple keys with Unix sort
I have potentially large files that need to be sorted by 1-n keys. Some of these keys might be numeric and some of them might not be. This is a fixed-width columnar file so there are no delimiters.
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Reduce, fold or scan (Left/Right)?
...hrough the first argument res of our binary operator minus:
val xs = List(1, 2, 3, 4)
def minus(res: Int, x: Int) = {
println(s"op: $res - $x = ${res - x}")
res - x
}
xs.reduceLeft(minus)
// op: 1 - 2 = -1
// op: -1 - 3 = -4 // de-cumulates value -1 in *first* operator arg `res`
// op: -4 - ...
Extract elements of list at odd positions
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Solution
Yes, you can:
l = L[1::2]
And this is all. The result will contain the elements placed on the following positions (0-based, so first element is at position 0, second at 1 etc.):
1, 3, 5
so the result (actual numbers) will be:
2, 4, 6
Exp...
How do I use floating-point division in bash?
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How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly
...0, 0, np.NaN], range(3), range(3)])
>>> df.isnull()
0 1 2
0 False False False
1 False True False
2 False False True
3 False False False
4 False False False
>>> df.isnull().any(axis=1)
0 False
1 True
2 True
3 False
4 False
dtype: bo...
How to get all subsets of a set? (powerset)
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137
The Python itertools page has exactly a powerset recipe for this:
from itertools import chain...