合并/合并pandas中的值

import pandas as pd

df1 = pd.DataFrame({
    'key': ['A', 'B', 'C', 'D'],
    'value1': [1, 2, 3, 4]
})

df2 = pd.DataFrame({
    'key': ['B', 'D', 'E', 'F'],
    'value2': [5, 6, 7, 8]
})

inner_join_df = pd.merge(df1, df2, on='key', how='inner')
print(inner_join_df)

  key  value1  value2
0   B       2       5
1   D       4       6

outer_join_df = pd.merge(df1, df2, on='key', how='outer')
print(outer_join_df)

  key  value1  value2
0   A     1.0     NaN
1   B     2.0     5.0
2   C     3.0     NaN
3   D     4.0     6.0
4   E     NaN     7.0
5   F     NaN     8.0

left_join_df = pd.merge(df1, df2, on='key', how='left')
print(left_join_df)

  key  value1  value2
0   A       1     NaN
1   B       2     5.0
2   C       3     NaN
3   D       4     6.0

right_join_df = pd.merge(df1, df2, on='key', how='right')
print(right_join_df)

  key  value1  value2
0   B     2.0       5
1   D     4.0       6
2   E     NaN       7
3   F     NaN       8

merged_df = pd.merge(df1, df2, on='key', suffixes=('_left', '_right'))
print(merged_df)

  key  value1_left  value2_right
0   B           2            5
1   D           4            6

outer_join_df = pd.merge(df1, df2, on='key', how='outer')
print(outer_join_df)