Pandas 使用变量作为列名
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时间：2020-09-14 00:56:31 来源:igfitidea点击:
Pandas use variable for column names
提问by Dance Party
Given the following data frame:
给定以下数据框：
import pandas as pd
import numpy as np
df = pd.DataFrame({'A':[1,2,3],
'B':[4,5,6],
'C':[7,8,9]})
df
A B C
0 1 4 7
1 2 5 8
2 3 6 9
How can I access columns via a variable?
如何通过变量访问列？
I tried this:
我试过这个：
cols='A','B'
df[cols]
...which resulted in this:
...导致了这个：
KeyError: ('A', 'B')
Bonus Question: What if my data frame were like this?:
额外问题：如果我的数据框是这样的怎么办？：
import pandas as pd
import numpy as np
df = pd.DataFrame({'A':[1,2,3],
'B':[4,5,6],
'C':[7,8,9],
'D':[1,3,5],
'E':[5,3,6],
'F':[7,4,3]})
df
A B C D E F
0 1 4 7 1 5 7
1 2 5 8 3 3 4
2 3 6 9 5 6 3
and I wanted to do this?:
我想这样做？：
cols=['A','B']
cols2=['C','D']
df[cols,'F',cols2]
Thanks in advance!
提前致谢！
采纳答案by jezrael
You can try subset by listof column names:
您可以尝试按list列名进行子集：
cols=['A','B']
print df[cols]
A B
0 1 4
1 2 5
2 3 6
It is same as:
它与：
print df[['A','B']]
A B
0 1 4
1 2 5
2 3 6
Bonus answer:
奖金答案：
cols=['A','B']
cols2=['C','D']
allcols = cols + ['F'] + cols2
print df[allcols]
A B F C D
0 1 4 7 7 1
1 2 5 4 8 3
2 3 6 3 9 5
