how to set a column to index in 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 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 4: set index in datarame

df = df.set_index('col')

Example 5: set column as index

>>> df = df.set_index('Identifier')
>>> df.head()
                Place of Publication Date of Publication  \
206                           London         1879 [1878]
216         London; Virtue & Yorston                1868
218                           London                1869
472                           London                1851
480                           London                1857

                        Publisher  \
206              S. Tinsley & Co.
216                  Virtue & Co.
218         Bradbury, Evans & Co.
472                 James Darling
480          Wertheim & Macintosh

                                                        Title     Author  \
206                         Walter Forbes. [A novel.] By A. A      A. A.
216         All for Greed. [A novel. The dedication signed...  A., A. A.
218         Love the Avenger. By the author of “All for Gr...  A., A. A.
472         Welsh Sketches, chiefly ecclesiastical, to the...  A., E. S.
480         [The World in which I live, and my place in it...  A., E. S.

                                                   Flickr URL
206         http://www.flickr.com/photos/britishlibrary/ta...
216         http://www.flickr.com/photos/britishlibrary/ta...
218         http://www.flickr.com/photos/britishlibrary/ta...
472         http://www.flickr.com/photos/britishlibrary/ta...
480         http://www.flickr.com/photos/britishlibrary/ta...