Python | Count unique sublists within list

Last Updated : 16 Mar, 2019

Given a list of lists, the task is to find the count of unique sublists within list.

Examples:

Input: [['Geek', 'for', 'geeks'], ['geeks', 'for'],
        ['for', 'Geeks', 'geek'], ['Geek', 'for', 'geeks']]

Output:
{('geeks', 'for'): 1, ('for', 'Geeks', 'geek'): 1, 
 ('Geek', 'for', 'geeks'): 2}

Below are some ways to achieve the task.

Method #1: Using Iteration

# Python code to count unique sublist within list 
  
# Input list initialization 
Input = [['Geek', 'for', 'geeks'], ['geeks', 'for'], 
         ['for', 'Geeks', 'geek'], ['Geek', 'for', 'geeks']] 
  
# Output list initialization 
Output = {} 
  
# Using Iteration 
for lis in Input: 
    Output.setdefault(tuple(lis), list()).append(1) 
for a, b in Output.items(): 
    Output[a] = sum(b) 
  
# Printing output 
print(Output) 

Output:

{(‘Geek’, ‘for’, ‘geeks’): 2, (‘geeks’, ‘for’): 1, (‘for’, ‘Geeks’, ‘geek’): 1}

Method #2: Using Counter

# Python code to find count of unique list in list of list 
  
# Importing counter from collection 
from collections import Counter 
  
# Input list initialization 
lst = [[1, 2, 3], [4, 5, 6], [3, 2, 1], [1, 2, 3]] 
  
# Using counter 
Output = Counter([tuple(i) for i in lst]) 
  
# Printing output 
print(Output) 

Output:

Counter({(1, 2, 3): 2, (3, 2, 1): 1, (4, 5, 6): 1})

Method #3: Using Pandas

# Python code to count unique sublist within list 
  
# Importing  
from collections import Counter 
import pandas as pd                      
  
# Input list initialization 
lst = [[1, 2, 3], [4, 5, 6], [3, 2, 1], [1, 2, 3]] 
  
# Getting count 
dict = Counter([tuple(i) for i in lst]) 
  
# Creating pandas dataframe 
Output = pd.DataFrame(data ={'list': list(dict.keys()), 
                         'count': list(dict.values())}) 
  
# Printing output 
print(Output) 

Output:

count       list
0      1  (3, 2, 1)
1      1  (4, 5, 6)
2      2  (1, 2, 3)

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