pandas uses Groupby to iterate over groups

#-*- coding:utf-8 -*-
import pandas as pd
import numpy as np
df=pd.DataFrame({
    
    'key1':['a','a','b','b','a'],'key2':['one','two','one','two','one'],
                 'data1':np.random.randn(5),'data2':np.random.randn(5)})
 
for name,group in df.groupby('key1'):
    print(name)  # 'key1'列去重后的结果，去重后为['a', 'b']
    print(group)

#结果：
a
##########################################################
      data1     data2 key1 key2
0 -1.389589  0.605121    a  one
1  0.057731  1.387236    a  two
4  0.973961 -1.540356    a  one
##########################################################
b
      data1     data2 key1 key2
2 -0.476933 -0.110656    b  one