df.reset_index(level=0, inplace=True)
import numpy as np import pandas as pd df = pd.DataFrame({'month': [2, 5, 8, 10], 'year': [2017, 2019, 2018, 2019], 'sale': [60, 45, 90, 36]}) df.set_index('month')
df = df.set_index('col')