How to find the number of unique values in comma separated strings stored in an pandas data frame column?

Question

x	Unique_in_x
5,5,6,7,8,6,8	4
5,9,8,0	4
5,9,8,0	4
3,2	2
5,5,6,7,8,6,8	4

Unique_in_x is my expected column.Sometime x column might be string also.

Answer 1

You can use a list comprehension with a set

df['Unique_in_x'] = [len(set(x.split(','))) for x in df['x']]

Or using a split and nunique :

df['Unique_in_x'] = df['x'].str.split(',', expand=True).nunique(1)

Output:

               x  Unique_in_x
0  5,5,6,7,8,6,8            4
1        5,9,8,0            4
2        5,9,8,0            4
3            3,2            2
4  5,5,6,7,8,6,8            4

Answer 2

You can find the unique value of the list with np.unique() and then just use the length

import pandas as pd
import numpy as np

df['Unique_in_x'] = df['X'].apply(lambda x : len(np.unique(x.split(','))))