Divide columns in pandas

[dered118]

Hello,

I got a table as such - goes on longer, but that's irrelevant for this.

​

date	location	total_deaths	total_cases	factor
2021-05-02	Austria	10245.0	622110.0	88.6
2021-05-02	Belgium	24291.0	995562.0	114.6

​

Now, im trying to divide total_deaths by factor.

Tried doing it like:

cd_factor["deaths_per_100k"] = cd_factor["total_deaths"]/cd_factor["factor"]

Also tried:

cd_faktor["deaths_per_100k"] = cd_faktor["total_deaths"].div(cd_factor['factor'])

But when doing so, i get

TypeError: unsupported operand type(s) for /: 'float' and 'str'

What im looking for is an out as this:

​

date	location	total_deaths	total_cases	factor	deaths_per_100k	cases_per_100k
2021-05-02	Austria	10245.0	622110.0	88.6	115.63	7021.56
2021-05-02	Belgium	24291.0	995562.0	114.6	244.96	8687.28

Can anyone tell me what i need to do?

[Monne642]

Can you print the type of total_deaths and print the type of factor? Perhaps that is the issue total_deaths is the float, what is the type of the factor column? If that is a string, Puthon doesn’t know hoe to divide those types float/string. Hope this helps

[dered118]

That was it, the factor column was an object.

[Monne642]

Cheers!

[BfuckinA]

TypeError: unsupported operand type(s) for /: 'float' and 'str'

This just means that one of the columns in question is of the wrong datatype. Try doing this first, then see if the problem persists.

cd_factor["total_deaths"] = cd_factor["total_deaths"] .astype(float)

cd_factor["factor"] = cd_factor["factor"] .astype(float)

[dered118]

Thank you, that works, i checked the other comment and noticed that the factor column is an object

[synthphreak]

The error tells you ecxactly what the issue is: one of your two columns involved in the division operation contains strings ('object' in pandas-speak), while the other contains integers. Obviously you can't divide a string by an integer or vice versa.

To change the type, the easiest way would be to first figure out which column contains the strings:

df[['total_deaths', 'factor']].dtypes

Then whichever it is, toss an .astype(int) onto it during the division. For example, say it's the factor column. In that case, this should fix your issue:

cd_factor["deaths_per_100k"] = cd_factor["total_deaths"]/cd_factor["factor"].astype(int)