Fast way to split column into multiple rows in Pandas

Question

I have the following data frame:

import pandas as pd
df = pd.DataFrame({ \'gene\':[\"foo\",
                            \"bar // lal\",
                                  


        

Answer 1

Or use:

df.join(pd.DataFrame(df.gene.str.split(',', expand=True).stack().reset_index(level=1, drop=True)
                ,columns=['gene '])).drop('gene',1).rename(columns=str.strip).reset_index(drop=True)

Output:

   gene  cell1  cell2
0   foo      5     12
1   bar      9     90
2   lal      9     90
3   qux      1     13
4   woz      7     87