pandas dividing rows by its total

Question

I have this df:

Name    num1  num2   num3  
A       1      2      3    
B       4      5      6    
C       7      8      9    

My goal is to divide each row by the total. This is what I came up with:

df.loc[:,"num1":"num3"] = df.loc[:,"num1":"num3"].div(df["total"], axis=0)

It works well. However, if there are more "numx" columns added in after num3, I would have to manually update the code to "num1":"numx". Is there a way to work around this?

Answer 1

first select matching columns:

In [21]: cols = df.columns[df.columns.str.contains('^num\d+')]

then divide elements in those rows by their sum (calculated for each row):

In [22]: df[cols] = df[cols].div(df[cols].sum(axis=1), axis=0)

In [23]: df
Out[23]:
  Name      num1      num2   num3
0    A  0.166667  0.333333  0.500
1    B  0.266667  0.333333  0.400
2    C  0.291667  0.333333  0.375

Answer 2

You need select_dtypes

df.loc[:,df.select_dtypes(exclude='object').columns]=df.select_dtypes(exclude='object').div(df.select_dtypes(exclude='object').sum(1),0)

df
Out[66]: 
  Name      num1      num2   num3
0    A  0.166667  0.333333  0.500
1    B  0.266667  0.333333  0.400
2    C  0.291667  0.333333  0.375

Answer 3

You can use apply function and apply the division on each row. It'll give same results.

df = df.apply(lambda x = x.div(x.sum()), axis=1)