Python Pandas 中每一列元素的平方
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时间：2020-08-18 20:55:25 来源:igfitidea点击:
Square of each element of a column in pandas
提问by Pierpaolo
How can I square each element of a column/series of a DataFrame in pandas (and create another column to hold the result)?
如何在 Pandas 中对 DataFrame 的列/系列的每个元素进行平方（并创建另一列来保存结果）？
采纳答案by alko
>>> import pandas as pd
>>> df = pd.DataFrame([[1,2],[3,4]], columns=list('ab'))
>>> df
a b
0 1 2
1 3 4
>>> df['c'] = df['b']**2
>>> df
a b c
0 1 2 4
1 3 4 16
回答by postelrich
Nothing wrong with the accepted answer, there is also:
接受的答案没有错，还有：
df = pd.DataFrame({'a': range(0,100)})
np.square(df)
np.power(df, 2)
Which is ever so slightly faster:
哪个稍微快一点：
In [11]: %timeit df ** 2
10000 loops, best of 3: 95.9 μs per loop
In [13]: %timeit np.square(df)
10000 loops, best of 3: 85 μs per loop
In [15]: %timeit np.power(df, 2)
10000 loops, best of 3: 85.6 μs per loop
