pandas数据帧将行合并为列

import pandas as pd

df1 = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})
df2 = pd.DataFrame({'C': [7, 8, 9], 'D': [10, 11, 12]})

result = pd.concat([df1, df2], axis=1)
print(result)

   A  B  C   D
0  1  4  7  10
1  2  5  8  11
2  3  6  9  12

import pandas as pd

df1 = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})
df2 = pd.DataFrame({'A': [7, 8, 9], 'B': [10, 11, 12]})

result = pd.merge(df1, df2, how='outer')
print(result)

   A   B
0  1   4
1  2   5
2  3   6
3  7  10
4  8  11
5  9  12

import pandas as pd

df1 = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]}, index=[0, 1, 2])
df2 = pd.DataFrame({'C': [7, 8, 9], 'D': [10, 11, 12]}, index=[0, 1, 2])

result = df1.join(df2, how='outer')
print(result)

   A  B  C   D
0  1  4  7  10
1  2  5  8  11
2  3  6  9  12