How to find the location index of a given Pandas dataframe index?

Question

In Python Pandas, how do you find the numerical index of a dataframe?

Consider the following example.

import pandas as pd

df = pd.DataFrame(np.arange(20).reshape(5,4), index = np.arange(2,7),columns=["A","B","C","D"])

Output:

    A   B   C   D
2   0   1   2   3
3   4   5   6   7
4   8   9  10  11
5  12  13  14  15
6  16  17  18  19

How do you find the location index of the df.index == 4. The answer should be 2.

Answer 1

Try .get_loc

In [4]: df.index.get_loc(4)
Out[4]: 2

Answer 2

Check get_indexer notice the different here is get_loc will do one value per called , get_indexer you can pass a list

df.index.get_indexer([4])
array([2], dtype=int64)