how to use a column as index pandas code example

Example 1: 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')

Example 2: define a column as index pandas

myDataFrame.set_index('column_name')