Python 2.7 Pandas-查找各组中值的百分比

我有一个csv文件，如下所示

Beat,Hour,Month,Primary Type,COUNTER
111,10AM,Apr,ASSAULT,12
111,10AM,Apr,BATTERY,5
111,10AM,Apr,BURGLARY,1
111,10AM,Apr,CRIMINAL DAMAGE,4
111,10AM,Aug,MOTOR VEHICLE THEFT,2
111,10AM,Aug,NARCOTICS,1
111,10AM,Aug,OTHER OFFENSE,18
111,10AM,Aug,THEFT,38

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现在，我想找到由前三列分组的每个主要类型的百分比。例如，对于节拍=111，小时=上午10点，月份=4月，%attack=12/（12+5+1+4）*100。有人能给你一个关于如何使用熊猫做这件事的线索吗？

你可以使用

transform

sum

df['New']=df.COUNTER/df.groupby(['Beat','Hour','Month']).COUNTER.transform('sum')*100
df
Out[575]: 
   Beat  Hour Month         Primary Type  COUNTER        New
0   111  10AM   Apr              ASSAULT       12  54.545455
1   111  10AM   Apr              BATTERY        5  22.727273
2   111  10AM   Apr             BURGLARY        1   4.545455
3   111  10AM   Apr      CRIMINAL DAMAGE        4  18.181818
4   111  10AM   Aug  MOTOR VEHICLE THEFT        2   3.389831
5   111  10AM   Aug            NARCOTICS        1   1.694915
6   111  10AM   Aug        OTHER OFFENSE       18  30.508475
7   111  10AM   Aug                THEFT       38  64.406780

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谢谢它帮助了@buddingengineer yw~：-）愉快的编码