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Single Line Nested For Loops
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172
The best source of information is the official Python tutorial on list comprehensions. List com...
How to compare two strings in dot separated version format in Bash?
Is there any way to compare such strings on bash, e.g.: 2.4.5 and 2.8 and 2.4.5.1 ?
29 Answers
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How to add new item to hash
...eate the hash:
hash = {:item1 => 1}
Add a new item to it:
hash[:item2] = 2
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How do you plot bar charts in gnuplot?
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124
Simple bar graph:
set boxwidth 0.5
set style fill solid
plot "data.dat" using 1:3:xtic(2) wi...
pandas GroupBy columns with NaN (missing) values
...e groupby (e.g. -1):
In [11]: df.fillna(-1)
Out[11]:
a b
0 1 4
1 2 -1
2 3 6
In [12]: df.fillna(-1).groupby('b').sum()
Out[12]:
a
b
-1 2
4 1
6 3
That said, this feels pretty awful hack... perhaps there should be an option to include NaN in groupby (see this github issue ...
Selecting with complex criteria from pandas.DataFrame
... in range(10)]})
>>> df
A B C
0 9 40 300
1 9 70 700
2 5 70 900
3 8 80 900
4 7 50 200
5 9 30 900
6 2 80 700
7 2 80 400
8 5 80 300
9 7 70 800
We can apply column operations and get boolean Series objects:
>>> df["B"] > 50
0 False
1 T...
Remove empty elements from an array in Javascript
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1151
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`elif` in list comprehension conditionals
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259
Python's conditional expressions were designed exactly for this sort of use-case:
>>>...
SQL Logic Operator Precedence: And and Or
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296
And has precedence over Or, so, even if a <=> a1 Or a2
Where a And b
is not the same...