Pandas generating colun

I have the following df:

from    to  

5   7   

8   10  

I am trying to get the following output:

from    to  zip_1   zip_2   zip_3   zip_4

5   8   5   6   7   8

9   10  9   10      

I tried the following code but resulted in an error.

for index, row in df.iterrows():
    zip_index = 0
    colName = 'zip' + '_' + str(zip_index)
    while row(colName) != row.To: 
        zip_index = zip_index + 1
        NewCol = 'zip' + '_' + str(zip_index)
        row(NewCol) = row(colName) + 1
        colName = NewCol

What am I missing?

Thanks!