PYTHON

pandas set a column as index

df = pd.DataFrame({'month': [1, 4, 7, 10],
                   'year': [2012, 2014, 2013, 2014],
                   'sale': [55, 40, 84, 31]})

df.set_index('month')

set index to column pandas

# method A
df = df.set_index('col')
# method B
df['col'] = df.index

Set column as index with pandas

import pandas as pd

# Set column as index
df = df.set_index("column")

# Display DataFrame
print(df)