The main task of map() is used to map the values from two series that have a common column. To map the two Series, the last column of the first Series should be the same as the index column of the second series, and the values should be unique.
It returns the Pandas Series with the same index as a caller.
0 Core 1 NaN 2 NaN 3 NaN dtype: object
0 I like Java 1 I like C 2 I like C++ 3 I like nan dtype: object
0 I like Java 1 I like C 2 I like C++ 3 NaN dtype: object