为什么 Pandas 给出 AttributeError: 'SeriesGroupBy' 对象没有属性 'pct'？
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Why Pandas gives AttributeError: 'SeriesGroupBy' object has no attribute 'pct'?
提问by Franco Piccolo
I'm trying to pass a user defined function pctto Pandas aggmethod, and it works if I only pass that function but it doesn't when I use the dictionary format for defining the functions. Does anyone know why?
我正在尝试将用户定义的函数传递pct给 Pandasagg方法，如果我只传递该函数，它会起作用，但当我使用字典格式定义函数时则不会。有谁知道为什么？
import pandas as pd
df = pd.DataFrame([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]],
columns=['A', 'B', 'C'])
pct = lambda x: len(x)/len(df)
df.groupby('A').agg(pct)
returns as expected
按预期返回
B C
A
1 0.333333 0.333333
4 0.333333 0.333333
7 0.333333 0.333333
But
但
aggs = {'B':['pct']}
df.groupby('A').agg(aggs)
returns the following error:
返回以下错误：
AttributeError: 'SeriesGroupBy' object has no attribute 'pct'
回答by jezrael
There is string 'pct', need variable pct- lambda function by removing '':
有字符串'pct'，需要pct通过删除变量- lambda 函数''：
aggs = {'B':pct}
print(df.groupby('A').agg(aggs))
B
A
1 0.333333
4 0.333333
7 0.333333
