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How to apply a function to two columns of Pandas dataframe
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318
Here's an example using apply on the dataframe, which I am calling with axis = 1.
Note the d...
How to iterate for loop in reverse order in swift?
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233
Xcode 6 beta 4 added two functions to iterate on ranges with a step other than one:
stride(from...
Programmatically Lighten or Darken a hex color (or rgb, and blend colors)
...n or darken a hex color by a specific amount. Just pass in a string like "3F6D2A" for the color ( col ) and a base10 integer ( amt ) for the amount to lighten or darken. To darken, pass in a negative number (i.e. -20 ).
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Fast permutation -> number -> permutation mapping algorithms
I have n elements. For the sake of an example, let's say, 7 elements, 1234567. I know there are 7! = 5040 permutations possible of these 7 elements.
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Pandas groupby: How to get a union of strings
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In [5]: df
Out[5]:
A B C
0 1 0.749065 This
1 2 0.301084 is
2 3 0.463468 a
3 4 0.643961 random
4 1 0.866521 string
5 2 0.120737 !
In [6]: df.dtypes
Out[6]:
A int64
B float64
C object
dtype: object
When you apply your own function, t...
Fastest way to check if a string matches a regexp in ruby?
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answered Mar 16 '17 at 12:30
Wiktor StribiżewWiktor Stribiżew
432k2323 gold badges250250 silver badges335335 bronze badges
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Difference between map, applymap and apply methods in Pandas
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Straight from Wes McKinney's Python for Data Analysis book, pg. 132 (I highly recommended this book):
Another frequent operation is applying a function on 1D arrays to each column or row. DataFrame’s apply method does exactly this:
In [116]: frame = DataFrame(np.random.randn(4, 3),...
Convert floats to ints in Pandas?
...f= pd.DataFrame(range(5), columns=['a'])
df.a = df.a.astype(float)
df
Out[33]:
a
0 0.0000000
1 1.0000000
2 2.0000000
3 3.0000000
4 4.0000000
pd.options.display.float_format = '{:,.0f}'.format
df
Out[35]:
a
0 0
1 1
2 2
3 3
4 4
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Logical operators for boolean indexing in Pandas
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3 Answers
3
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Extract first item of each sublist
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Using list comprehension:
>>> lst = [['a','b','c'], [1,2,3], ['x','y','z']]
>>> lst2 = [item[0] for item in lst]
>>> lst2
['a', 1, 'x']
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