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Most efficient way to reverse a numpy array
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edited May 23 '17 at 12:26
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answered Jul 21 '11 at 5:25
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Rails 3 migrations: Adding reference column?
If I create a new rails 3 migration with (for example)
10 Answers
10
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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 ...
How can I make pandas dataframe column headers all lowercase?
...x in data.columns]
example:
>>> data = pd.DataFrame({'A':range(3), 'B':range(3,0,-1), 'C':list('abc')})
>>> data
A B C
0 0 3 a
1 1 2 b
2 2 1 c
>>> data.columns = map(str.lower, data.columns)
>>> data
a b c
0 0 3 a
1 1 2 b
2 2 1 c
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Is inject the same thing as reduce in ruby?
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edited May 9 '14 at 7:03
answered Dec 11 '12 at 3:44
Zac...
How to take column-slices of dataframe in pandas
...ing to 'bar'
df.loc[:, :'bar']
# foo bar
# slice from 'quz' to the end by 3
df.loc[:, 'quz'::3]
# quz sat
# attempt from 'sat' to 'bar'
df.loc[:, 'sat':'bar']
# no columns returned
# slice from 'sat' to 'bar'
df.loc[:, 'sat':'bar':-1]
sat cat ant quz bar
# slice notation is syntatic sugar for th...
How to use a custom comparison function in Python 3?
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53
Use the key argument (and follow the recipe on how to convert your old cmp function to a key fun...
Convert all strings in a list to int
...the map function (in Python 2.x):
results = map(int, results)
In Python 3, you will need to convert the result from map to a list:
results = list(map(int, results))
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