How to convert a column value to list in Python

Question

I need to convert the value in the column 'value' to a list format. The dataframe df:

    emp_no  value
0   390     10.0
1   395     20.0
2   397     30.0
3   522     40.0
4   525     40.0

Output should be:

    emp_no  value
0   390     [5,10.0]
1   395     [5,20.0]
2   397     [5,30.0]
3   522     [5,40.0]
4   525     [5,40.0]

Answer 1

You could try with map, as well :

import pandas as pd

df = pd.DataFrame({'em_pno':[390,396,397], 'value':[10.0,6.0,7.0]})
df['value'] = df['value'].map(lambda x:[5, x])

# IN
   em_pno  value
0     390   10.0
1     396    6.0
2     397    7.0
# OUT
   em_pno      value
0     390  [5, 10.0]
1     396   [5, 6.0]
2     397   [5, 7.0]