在两个维度中创建两个pandas数据帧的组合

Question

我有两个pandas数据帧,df1和df2.我想创建一个数据帧df3,其中包含使用df1中的一列和df2中的一列的所有组合.无效率地执行此操作的伪代码将是这样的:

df3 = []
for i in df1:
     for j in df2:
         df3.append(i + j) # where i + j is the row with the combined cols from df1 and df2

这是df1的格式:

df1_id    other_data_1    other_data_2
1         0               1
2         1               5

DF2:

df2_id    other_data_3    other_data_4
1         0               1
3         2               2

目标是为df3获取此输出:

df1_id    df2_id    other_data_1    other_data_2    other_data_3    other_data_4
1         1         0               1               0               1
1         3         0               1               2               2
2         1         1               5               0               1
2         3         1               5               2               2

Answer 1

在两个数据帧之间设置公共密钥并使用pd.merge:

df1['key'] = 1
df2['key'] = 1

合并和删除键列:

df3 = pd.merge(df1,df2,on='key').drop('key',axis=1)
df3

输出:

   df1_id  other_data_1  other_data_2  df2_id  other_data_3  other_data_4
0       1             0             1       1             0             1
1       1             0             1       3             2             2
2       2             1             5       1             0             1
3       2             1             5       3             2             2