Q: Python: how to add zeros to the entries of a data frame column? I have a data frame contains the information of some ids.
df  
    ID
0   34
1   756
2   1090
3   3
4   45
5   549020

I would like to add some zeros before each ids in order to get ids of 8 digits, in order to get:
df  
    ID
0   00000034
1   00000756
2   00001090
3   00000003
4   00000045
5   00549020

