相当于Excel VLOOKUP的熊猫

我认为您需要

map

A

df['C'] = df.B.map(df.A)print (df)   A          B      CIndex      2001-06-30  100 2001-08-31  300.02001-07-31  200 2001-09-30  400.02001-08-31  300 2001-10-31    NaN2001-09-30  400 2001-11-30    NaN

与以下内容相同：

df['C'] = df.B.map(df.A.to_dict())print (df)   A          B      CIndex      2001-06-30  100 2001-08-31  300.02001-07-31  200 2001-09-30  400.02001-08-31  300 2001-10-31    NaN2001-09-30  400 2001-11-30    NaN