根据 PythonPandas 中的连接从第二个表中 Select 随机值

假设这就是您要开始的内容:

df1

  label
0     A
1     B
2     C
3     A
4     B

df2

  label  value
0     C      5
1     B      8
2     C      1
3     B      2
4     A      3
5     A      4
6     B      5
7     A      2
8     B      7

Option 1: Merge on cumcounted key
One easy way to do this is to shuffle df2, add an incremental key to both dataFrames and then merge:

df3 = df1.assign(key=df1.groupby('label').cumcount())
df4 = (df2.sample(frac=1)
          .reset_index(drop=True)
          .assign(key=lambda d: d.groupby('label').cumcount()))

df3.merge(df4, how='left', on=['label', 'key']).drop('key', 1)

  label  value
0     A      2
1     B      5
2     C      1
3     A      3
4     B      8

注:确定性洗牌设置为np.random.seed

Option 2: Sample groups and concat
Another option is to groupby df2, sample groups and concat

counts = df1['label'].value_counts() 
pd.concat([g.sample(n=counts[k]) for k, g in df2.groupby('label')])

  label  value
7     A      2
5     A      4
3     B      2
6     B      5
2     C      1

这里需要注意的是，不会保留顺序.