问题
Objective
I have this df and take some ratios below. I want to calculate these ratios by each id and datadate and I believe the groupby function is the way to go, however I am not exactly sure. Any help would be super!
df
id datadate dltt ceq ... pstk icapt dlc sale
1 001004 1975-02-28 3.0 193.0 ... 1.012793 1 0.20 7.367237
2 001004 1975-05-31 4.0 197.0 ... 1.249831 1 0.21 8.982741
3 001004 1975-08-31 5.0 174.0 ... 1.142086 2 0.24 8.115609
4 001004 1975-11-30 8.0 974.0 ... 1.400673 3 0.26 9.944990
5 001005 1975-02-28 3.0 191.0 ... 1.012793 4 0.25 7.367237
6 001005 1975-05-31 3.0 971.0 ... 1.249831 5 0.26 8.982741
7 001005 1975-08-31 2.0 975.0 ... 1.142086 6 0.27 8.115609
8 001005 1975-11-30 1.0 197.0 ... 1.400673 3 0.27 9.944990
9 001006 1975-02-28 3.0 974.0 ... 1.012793 2 0.28 7.367237
10 001006 1975-05-31 4.0 74.0 ... 1.249831 1 0.21 8.982741
11 001006 1975-08-31 5.0 75.0 ... 1.142086 3 0.23 8.115609
12 001006 1975-11-30 5.0 197.0 ... 1.400673 4 0.24 9.944990
Example of ratios
df['capital_ratioa'] = df['dltt']/(df['dltt']+df['ceq']+df['pstk'])
df['equity_invcapa'] = df['ceq']/df['icapt']
df['debt_invcapa'] = df['dltt']/df['icapt']
df['sale_invcapa']=df['sale']/df['icapt']
df['totdebt_invcapa']=(df['dltt']+df['dlc'])/df['icapt']
回答1:
Is this what you're looking for?
df = df.groupby(by=['id'], as_index=False).sum()
df['capital_ratioa'] = df['dltt']/(df['dltt']+df['ceq']+df['pstk'])
df['equity_invcapa'] = df['ceq']/df['icapt']
df['debt_invcapa'] = df['dltt']/df['icapt']
df['sale_invcapa']=df['sale']/df['icapt']
df['totdebt_invcapa']=(df['dltt']+df['dlc'])/df['icapt']
print(df)
Output:
id dltt ceq pstk icapt dlc sale capital_ratioa equity_invcapa debt_invcapa sale_invcapa totdebt_invcapa
0 1004 20.0 1538.0 4.805383 7 0.91 34.410577 0.012797 219.714286 2.857143 4.915797 2.987143
1 1005 9.0 2334.0 4.805383 18 1.05 34.410577 0.003833 129.666667 0.500000 1.911699 0.558333
2 1006 17.0 1320.0 4.805383 10 0.96 34.410577 0.012669 132.000000 1.700000 3.441058 1.796000
来源：https://stackoverflow.com/questions/61902540/groupby-id-to-calculate-ratios