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What is monkey patching?
...= just_foo_cols # monkey-patch the DataFrame class
df = pd.DataFrame([list(range(4))], columns=["A","foo","foozball","bar"])
df.just_foo_cols()
del pd.DataFrame.just_foo_cols # you can also remove the new method
To break this down, first we import our module:
import pandas as pd
Next we create ...
How do I get the opposite (negation) of a Boolean in Python?
...
Also, int in range (....) is inefficient. It will create a list and then perform a linear search. Better than x in range(low, high) is low <= x < high.
– MRAB
Aug 11 '11 at 19:24
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Returning first x items from array
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A more object oriented way would be to provide a range to the #[] method. For instance:
Say you want the first 3 items from an array.
numbers = [1,2,3,4,5,6]
numbers[0..2] # => [1,2,3]
Say you want the first x items from an array.
numbers[0..x-1]
The great thing a...
How to determine the encoding of text?
...pecified number of lines
rawdata = b''.join([f.readline() for _ in range(n_lines)])
return chardet.detect(rawdata)['encoding']
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How to get commit history for just one branch?
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You can use a range to do that.
git log master..
If you've checked out your my_experiment branch. This will compare where master is at to HEAD (the tip of my_experiment).
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Why does Python use 'magic methods'?
...ted in Python. That's more a bug than a feature, though (e.g. Python 3.2's range object can mostly handle arbitrarily large ranges, but using len with them may fail. Their __len__ fails as well though, since they're implemented in C rather than Python)
– ncoghlan
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What is the syntax to insert one list into another list in python?
..., 'c', 3, 4, 5]
List slicing is quite flexible as it allows to replace a range of entries in a list with a range of entries from another list:
>>> l = [1, 2, 3, 4, 5]
>>> l[2:4] = ['a', 'b', 'c'][1:3]
>>> l
[1, 2, 'b', 'c', 5]
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Converting a column within pandas dataframe from int to string
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In [16]: df = DataFrame(np.arange(10).reshape(5,2),columns=list('AB'))
In [17]: df
Out[17]:
A B
0 0 1
1 2 3
2 4 5
3 6 7
4 8 9
In [18]: df.dtypes
Out[18]:
A int64
B int64
dtype: object
Convert a series
In [19]: df['A'].apply(...
Understanding how recursive functions work
...o be bigger than b, then the answer is 0 - there aren't any numbers in the range! Therefore, we'll structure our solution as follows:
If a > b, then the answer is 0.
Otherwise (a ≤ b), get the answer as follows:
Compute the sum of the integers between a + 1 and b.
Add a to get the answer.
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What does axis in pandas mean?
...me process on dataframe2.
Basically,
stacking dataframe2 sideways.
E.g arranging books on a bookshelf.
More to it, since arrays are better representations to represent a nested n-dimensional structure compared to matrices! so below can help you more to visualize how axis plays an important rol...