How isolate between two times in pandas data frame and then modify just those values in a larger pandas dataframe?

Question

I have a large pandas dataframe. I want to select a subset (time range) of the dataframe and modify it by multiplying it by -1. I was trying something like this but it didn't work. Any suggestions?

g[g.between_time('22:55:00', '22:59:35')] =  g[g.between_time('22:55:00', '22:59:35')] * -1

Answer 1

使用update ：

g.update(g[g.between_time('22:55:00', '22:59:35')] * -1)