The lower() method maps character values to lowercase.
Example Prerequisite
>>> df = DataFrame('sales')
>>> df
Feb Jan Mar Apr datetime
accounts
Alpha Co 210.0 200 215 250 04/01/2017
Red Inc 200.0 150 140 None 04/01/2017
Orange Inc 210.0 None None 250 04/01/2017
Jones LLC 200.0 150 140 180 04/01/2017
Yellow Inc 90.0 None None None 04/01/2017
Blue Inc 90.0 50 95 101 04/01/2017
Example
>>> df.assign(drop_columns = True, lower = df.accounts.str.lower())
lower
0 alpha co
1 red inc
2 orange inc
3 jones llc
4 yellow inc
5 blue inc
Example
>>> df[df.accounts.str.lower() == 'orange inc']
Feb Jan Mar Apr datetime
accounts
Orange Inc 210.0 None None 250 04/01/2017