set index column 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: set index to column pandas

df = df.set_index('col')
df['col'] = df.index

Example 3: how to set index pandas

# assignment copy
df = df.set_index('month')

# or inplace
df.set_index('month', inplace=True)

#      year   sale  month            month  year   sale
#  0   2012   55    1                1      2012   55
#  1   2014   40    4       =>       4      2014   40
#  2   2013   84    7                7      2013   84
#  3   2014   31    10               10     2014   31

Example 4: how to change indeces in pandas dataframe

>>> df.set_index('month')
       year  sale
month
1      2012    55
4      2014    40
7      2013    84
10     2014    31

Example 5: how to change index in dataframe python

index = [1,2]
df.index = index

Example 6: change index to dataframe pandas

#cree un indice par defaut sur la base de donnee
df.reset_index()