📅  最后修改于: 2022-03-11 14:46:27.127000             🧑  作者: Mango
df = pd.DataFrame()
df['X'] = [0, 3, 1, 1, 2, 2, 3, 3, 1, 2]
df['Y'] = [111.0, np.nan, np.nan, 112, 113, np.nan, 114, 115, np.nan, 116]
df['Y'] = df['Y'].fillna(df['X'])
print(df)