how to give name to column in pandas

1df.rename(columns={"A": "a", "B": "b", "C": "c"},
2errors="raise", inplace=True)
3

1#df.rename() will only return a new df with the new headers
2#df = df.rename() will change the heders of the current dataframe 
3df = df.rename(columns={"old_col1": "new_col1", "old_col2": "new_col2"})

1>gapminder.rename(columns={'pop':'population',
2                          'lifeExp':'life_exp',
3                          'gdpPercap':'gdp_per_cap'}, 
4                 inplace=True)
5 
6>print(gapminder.columns)
7 
8Index([u'country', u'year', u'population', u'continent', u'life_exp',
9       u'gdp_per_cap'],
10      dtype='object')
11 
12>gapminder.head(3)
13 
14       country  year  population continent  life_exp  gdp_per_cap
150  Afghanistan  1952     8425333      Asia    28.801   779.445314
161  Afghanistan  1957     9240934      Asia    30.332   820.853030
172  Afghanistan  1962    10267083      Asia    31.997   853.100710
18