set columns in dataframe code example

Example 1: change name of column pandas

#df.rename() will only return a new df with the new headers
#df = df.rename() will change the heders of the current dataframe 
df = df.rename(columns={"old_col1": "new_col1", "old_col2": "new_col2"})

Example 2: how to change the columns of a dataframe in python

new_columns = {"col1": "1st", "col2": "2nd"}
df_new = df.rename(columns=new_columns)

"""
 col1 | col2 | col3            1st | 2nd | col3
   a  |   d  |	 g              a  |  d  |  g
   b  |   e  |   h		=>      b  |  e  |  h
   c  |   f  |   i              c  |  f  |  i
"""

Example 3: how to give name to column in pandas

>gapminder.rename(columns={'pop':'population',
                          'lifeExp':'life_exp',
                          'gdpPercap':'gdp_per_cap'}, 
                 inplace=True)
 
>print(gapminder.columns)
 
Index([u'country', u'year', u'population', u'continent', u'life_exp',
       u'gdp_per_cap'],
      dtype='object')
 
>gapminder.head(3)
 
       country  year  population continent  life_exp  gdp_per_cap
0  Afghanistan  1952     8425333      Asia    28.801   779.445314
1  Afghanistan  1957     9240934      Asia    30.332   820.853030
2  Afghanistan  1962    10267083      Asia    31.997   853.100710