How to do calculation on row level with data frame in python?

Question

I have a data frame in python, and I want to do a simple calculation on row level. How can can I do it in Python?

Current Table

product ct	cost1	cost2	cost3
1000	10	100	20
2000	200	100	30

Calculation Concept

product ct	cost1	cost2	cost3
1000	10/1000	100/1000	20/1000
2000	200/2000	100/2000	30/2000

Wanted Output

product ct	cost1	cost2	cost3
1000	0.01	0.1	0.02
2000	0.1	0.05	0.015

In general, pandas functions that apply across a column or row will have an axis parameter — Michael Silverstein
– Michael Silverstein, Commented Jul 28, 2021 at 15:21

ThePyGuy · Accepted Answer · 2021-07-28 15:22:40Z

2

You can use pandas.DataFrame.filter to get the required columns (If you have the static columns, you can manually assign them to a list), and then use div to divide, and finally assign back all the values to the selected columns:

>>> cols = df[:0].filter(like='cost').columns.to_list()
>>> df[cols] = df[cols].div(df['product ct'], axis=0)

OUTPUT:

   product ct  cost1  cost2  cost3
0        1000   0.01   0.10  0.020
1        2000   0.10   0.05  0.015

answered Jul 28, 2021 at 15:22

ThePyGuy

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Comments

not_speshal · Accepted Answer · 2021-07-28 15:24:23Z

2

Try using divide along the required axis:

df[["cost1", "cost2", "cost3"]] = df[["cost1", "cost2", "cost3"]].divide(df["product ct"], axis=0)
>>> df
   product ct  cost1  cost2  cost3
0        1000   0.01   0.10  0.020
1        2000   0.10   0.05  0.015

edited Jul 28, 2021 at 15:24

answered Jul 28, 2021 at 15:18

not_speshal

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