renaming headers pandasd

df.rename(columns={"old_col1": "new_col1", "old_col2": "new_col2"})

>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

df = df.rename(columns={"old_col1": "new_col1", "old_col2": "new_col2"})

>gapminder.columns = ['country','year','population',
                     'continent','life_exp','gdp_per_cap']