根据Pandas中的id将列值从一个dataframe复制到另一个dataframe

import pandas as pd

# 创建示例DataFrame df1
data1 = {'id': [1, 2, 3], 'value': ['a', 'b', 'c']}
df1 = pd.DataFrame(data1)

# 创建示例DataFrame df2
data2 = {'id': [2, 3, 4], 'new_value': ['d', 'e', 'f']}
df2 = pd.DataFrame(data2)

# 使用merge()函数根据'id'列合并两个DataFrame
merged_df = df1.merge(df2, on='id', how='left')

# 更新df1中的'value'列为df2中匹配的'new_value'
df1.loc[merged_df['id'].notnull(), 'value'] = merged_df['new_value']

print(df1)

   id value
0   1     a
1   2     d
2   3     e

df1['id'] = df1['id'].astype(int)
df2['id'] = df2['id'].astype(int)