Finding count of distinct elements in DataFrame in each column

Question

I am trying to find the count of distinct values in each column using Pandas. This is what I did.

import pandas as pd
import numpy as np

# Generate data.
NR         


        

Answer 1

Need to segregate only the columns with more than 20 unique values for all the columns in pandas_python:

enter code here
col_with_morethan_20_unique_values_cat=[]
for col in data.columns:
    if data[col].dtype =='O':
        if len(data[col].unique()) >20:

        ....col_with_morethan_20_unique_values_cat.append(data[col].name)
        else:
            continue

print(col_with_morethan_20_unique_values_cat)
print('total number of columns with more than 20 number of unique value is',len(col_with_morethan_20_unique_values_cat))



 # The o/p will be as:
['CONTRACT NO', 'X2','X3',,,,,,,..]
total number of columns with more than 20 number of unique value is 25

Answer 2

Already some great answers here :) but this one seems to be missing:

df.apply(lambda x: x.nunique())

As of pandas 0.20.0, DataFrame.nunique() is also available.