向循环中的DF添加新列

import pandas as pd

df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})

# 使用assign()方法添加新列
df = df.assign(C=lambda x: x['A'] + x['B'])

print(df)

   A  B  C
0  1  4  5
1  2  5  7
2  3  6  9

import pandas as pd

df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})

# 直接给DataFrame赋值添加新列
df['C'] = df['A'] + df['B']

print(df)

   A  B  C
0  1  4  5
1  2  5  7
2  3  6  9