Python 使用pandas将值从一列替换到另一列？

我有一个数据帧：

       subtracted      Subs        hrs  
0      281871.120   450878.77      0.00    
1      221343.432   229535.34      0.00     
2      197454.408    32080.93      0.00    
3      41934.000    -9853.07     32080.93

我想将正值（关于Subs列）从减法列替换为hrs列

预期产出：

       subtracted      Subs        hrs  
0      281871.120   450878.77      281871.120   
1      221343.432   229535.34      221343.432    
2      197454.408    32080.93      197454.408    
3      41934.000    -9853.07       32080.93

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有人能给我建议正确的方法吗？

您可以用

loc

替换由正值创建的掩码，或者：

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对于由负值创建的掩码，可以使用：

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你能看看这个吗。

m = df['Subs'] > 0
df.loc[m, 'hrs'] = df['subtracted']

df['hrs'] = df['subtracted'].where(m, df['hrs'])

df['hrs'] = np.where(m, df['subtracted'], df['hrs'])

print (df)
   subtracted       Subs         hrs
0  281871.120  450878.77  281871.120
1  221343.432  229535.34  221343.432
2  197454.408   32080.93  197454.408
3   41934.000   -9853.07   32080.930

m = df['Subs'] < 0
df['hrs'] = np.where(m, df['hrs'], df['subtracted'])

df['hrs'] = df['subtracted'].mask(m, df['hrs'])