按条件转换行数

Question

我尝试按条件转换行数：

df.loc[df['file'] ==  '0.mp4','xmin'] = df['xmin']/4
df.loc[df['file'] ==  '2.mp4','xmin'] = df['xmin']/4
df.loc[df['file'] ==  '8.mp4','xmin'] = df['xmin']/4
df.loc[df['file'] ==  '10.mp4','xmin'] = df['xmin']/4

是否可以在一行中执行此操作？

这吗？

df.loc[df['file'] ==  '0.mp4','xmin'] = df['xmin']/4
df.loc[df['file'] ==  '2.mp4','xmin'] = df['xmin']/4
df.loc[df['file'] ==  '0.mp4','ymin'] = df['ymin']/4
df.loc[df['file'] ==  '2.mp4','ymin'] = df['ymin']/4

Answer 1

您可以使用pandas.Series.isin：

df.loc[df['file'].isin(['0.mp4', '2.mp4', '8.mp4', '10.mp4']), 'xmin'] = df['xmin'] / 4

Answer 2

将Series.isin用于list的支票隶属关系，也可以将= df['xmin']/4简化为/= 4：

df.loc[df['file'].isin(['0.mp4','2.mp4','8.mp4','10.mp4']),'xmin'] /= 4