Python Pivot数据框[重复]

Question

假设我正在处理一个数据集：# dummy dataset

import pandas as pd
data = pd.DataFrame({"A_id" : ["John","Deep","Julia","John","Sandy",'Deep'], 
                     "Month_id" : [12,3,5,4,5,7]})
data

如何将此数据框转换为如下内容：

A_id 是唯一的并且基于值和其他列的存在/不存在形成新列？

Answer 1

这是一种方法

# create a temp seq to order the duplicate rows for an id then pivot
# rename the columns

df2=df.assign(seq=df.groupby('A_id').cumcount()+1).pivot(index=['A_id'], columns= ['seq']).reset_index()
df2.columns=[col[0]+"_"+str(col[1]) if col[1]!="" else col[0] for col in df2.columns]
df2

A_id    Month_id_1  Month_id_2
0   Deep    3.0     7.0
1   John    12.0    4.0
2   Julia   5.0     NaN
3   Sandy   5.0     NaN