How can I repercentage a cell from several data points in Python Pandas?

Question

I've been browsing different questions here on Stackexchange but haven't figured out how to do what I need in Pandas. I think it'll ultimately be pretty simple!

I'm doing a task where a dataset has a bunch of products, and each product has a row for each of the stores it's located in. So, Product A will have individual lines for food, drugstore, Target, Walmart, etc. Then, its availability and the importance of that outlet is multiplied and I need to repercentage that result to equal 100%.

Right now I'm doing it manually in Excel/Google Sheets, but that's annoying and tedious. I can tell how to get the sum total of column E per Product by using Groupby, but I can't figure out how to then make that number appear for each product so that each figure from column E can be divided into it.

Anyone have suggestions? Link to example of what the dataset looks like

Answer 1

To get the sum to show up for every product you want to .transform('sum')

In one line:

df['Repercentaged'] = df.groupby('Product').Multiplied.transform(lambda x: x/x.sum())

But if you want to keep the Sum Column...

import pandas as pd

df['Sum'] = df.groupby('Product').Multiplied.transform('sum')
#    Location  Multiplied Product   Sum
#0       Food        0.09       A  0.88
#1  Drugstore        0.21       A  0.88
#2    Walmart        0.35       A  0.88
#3     Target        0.23       A  0.88
#4       Food        0.13       B  0.73
#5  Drugstore        0.13       B  0.73
#6    Walmart        0.25       B  0.73
#7     Target        0.22       B  0.73

df['Repercentaged'] = df['Multiplied']/df['Sum']