df.columns = ['V', 'W', 'X', 'Y', 'Z']df2.columns = stocks['Ticker'][:3]
[:3] is just use first 3
[5::] skip first 5
price price price
2021-01-11 131.90 15.00 179.07
2021-01-12 128.09 15.74 182.65
to
Ticker A AAL AAP
2021-01-11 131.90 15.00 179.07
2021-01-12 128.09 15.74 182.65