Calculate pro rata ownership using Python

Question

I am relatively new to Python so pardon my question if it's relatively basic (have not been able to find anything helpful online).

I have a dataframe that has 3 columns, Fund | Investor | Quantity, and need to insert a new column into my dataframe that calculates each investors' pro-rata ownership.

I assume looping through the dataframe is the best way to do this but am having issues.

and the first version was perfect, please don't include images of code! You can format it via the toolbar, there is one code button — Nico Albers, Mar 08 '19 at 22:39

score 0 · Answer 1 · answered Mar 08 '19 at 22:41

0

It would be very easy if you can post your code but for reference you can use like:

df['D'] = df['A'] + df['B'] + df['C']

try above way in your existing code. Let me know if it helps.

answered Mar 08 '19 at 22:41

Jitendra Banshpal

555
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score 0 · Answer 2 · answered Mar 08 '19 at 23:00

0

try:

df['percent'] = df['QTY'] / df.groupby('Fund')['QTY'].transform('sum') * 100

answered Mar 08 '19 at 23:00

Terry

2,761
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score 0 · Accepted Answer · answered Mar 08 '19 at 23:00

See this question. Therefore you can group and apply:

In [1]: df = pd.DataFrame([
   ...:     ['Fund 1','Investor A', 10],
   ...:     ['Fund 1','Investor B', 20],
   ...:     ['Fund 2','Investor A', 30],
   ...:     ['Fund 2','Investor B', 40],
   ...:     ['Fund 2','Investor C', 30],
   ...:     ['Fund 3','Investor A', 50],
   ...:     ['Fund 3','Investor B', 50],
   ...: ], columns=['Fund','Investor', 'Qty'])
   ...:

In [2]: df['wanted'] = df.groupby('Fund').Qty.apply(lambda x: x/x.sum())

In [3]: df
Out[3]:
     Fund    Investor  Qty    wanted
0  Fund 1  Investor A   10  0.333333
1  Fund 1  Investor B   20  0.666667
2  Fund 2  Investor A   30  0.300000
3  Fund 2  Investor B   40  0.400000
4  Fund 2  Investor C   30  0.300000
5  Fund 3  Investor A   50  0.500000
6  Fund 3  Investor B   50  0.500000

The last step towards the percentages will be easy for you.

Thank you for your answer and apologies for duplicating. This works as expected. I do get a message," 89: SettingWithCopyWarning", that i may need to look into — jrass, Mar 08 '19 at 23:31
You're welcome! For the warning see for example [this](https://stackoverflow.com/questions/20625582/how-to-deal-with-settingwithcopywarning-in-pandas). In case this doesn't help you feel free to open a new question :-) — Nico Albers, Mar 09 '19 at 08:49

Calculate pro rata ownership using Python

3 Answers3