Subtraction and division of columns on a pandas groupby object-CodePudding

I have a pandas DataFrame:

  Name  Col_1  Col_2 Col_3 
0     A    3     5    5
1     B    1     6    7
2     C    3     7    4
3     D    5     8    3

I need to create a Series object with the values of (Col_1-Col_2)/Col_3 using groupby, so basically this:

Name
A   (3-5)/5
B   (1-6)/7
C   (3-7)/4
D   (5-8)/3

Repeated names are a possiblty, hance the groupby usage. I Created a groupby object:

df.groupby['Name']

but it seems like no groupby method fits the bill for what I'm trying to do. How can I tackle this matter?

CodePudding user response：

res_df = (df['Col_1'] - df['Col_2']) / df['Col_3']
res_df = pd.Series(res_df, name='Result')

print(res_df)

0   -0.400000
1   -0.714286
2   -1.000000
3   -1.000000
Name: Result, dtype: float64

CodePudding user response：

Let's try:

df.set_index('Name').eval('(Col_1-Col_2)/Col_3')

Output:

Name
A   -0.400000
B   -0.714286
C   -1.000000
D   -1.000000
dtype: float64