如何在 Pandas DataFrame 中移动几行?

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时间:2020-09-14 03:09:33  来源:igfitidea点击:

How to shift several rows in a pandas DataFrame?

pythonpandasdataframeshift

提问by ShanZhengYang

I have the following pandas Dataframe:

我有以下Pandas数据框:

import pandas as pd
data = {'one' : pd.Series([1.], index=['a']), 'two' : pd.Series([1., 2.], index=['a', 'b']), 'three' : pd.Series([1., 2., 3., 4.], index=['a', 'b', 'c', 'd'])}
df = pd.DataFrame(data)
df = df[["one", "two", "three"]]


   one  two  three
a  1.0  1.0    1.0
b  NaN  2.0    2.0
c  NaN  NaN    3.0
d  NaN  NaN    4.0

I know how to shift elements by column upwards/downwards, e.g.

我知道如何按列向上/向下移动元素,例如

df.two = df.two.shift(-1)

   one  two  three
a  1.0  2.0    1.0
b  NaN  NaN    2.0
c  NaN  NaN    3.0
d  NaN  NaN    4.0

However, I would like to shift all elements in row aover two columns and all elements in row bover one column. The final data frame would look like this:

但是,我想将行中的所有元素a移到两列上,并将行中的所有元素b移到一列上。最终的数据框如下所示:

   one  two  three
a  NaN  NaN    1.0
b  NaN  NaN    2.0
c  NaN  NaN    3.0
d  NaN  NaN    4.0

How does one do this in pandas?

如何在Pandas中做到这一点?

采纳答案by Nickil Maveli

You can transpose the initial DFso that you have a way to access the row labels as column names inorder to perform the shiftoperation.

您可以转置首字母,DF以便您有办法将行标签作为列名称访问,以便执行shift操作。

Shift the contents of the respective columns downward by those amounts and re-transpose it back to get the desired result.

将相应列的内容向下移动这些数量,然后将其重新调回以获得所需的结果。

df_t = df.T
df_t.assign(a=df_t['a'].shift(2), b=df_t['b'].shift(1)).T

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