创建一个由其他列组合而成的列 [英] Create a column that's a combination of other columns

问题描述

我有一个3列的pandas数据框，我想创建一个新列，如下所示:

I have a pandas dataframe with 3 columns, and I want to create a new column as follows:

import pandas as pd
import numpy as np
np.random.seed(2019)
df = pd.DataFrame(np.random.randn(5,3), columns=['A','B','C'])
cols = df.abs().idxmax(axis = 1)
cols
0    C
1    A
2    A
3    B
4    B
dtype: object

我想创建一个列D，该列在索引0处采用C的值，在索引1处采用A的类，等等.换句话说，D根据对象cols.我确定我可以遍历索引并选择列，但是有更好的方法吗?

I want to create a column D that takes the value of C at index 0, A at index 1, etc.. In other words, D takes values from the appropriate column as per the object cols. I'm sure I can loop through the indices and pick the columns, but is there a better way to do this?

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