Python - Extract Unique values dictionary values

Python – Extract Unique values dictionary values

Difficulty Level : Basic
Last Updated : 22 Apr, 2020

Sometimes, while working with data, we can have problem in which we need to perform the extraction of only unique values from dictionary values list. This can have application in many domains such as web development. Lets discuss certain ways in which this task can be performed.

Method #1 : Using sorted() + set comprehension + values()
The combination of above functionalities can be used to perform this task. In this, we extract all the values using values() and set comprehension is used to get unique values compiled in list.

# Python3 code to demonstrate working of 
# Extract Unique values dictionary values
# Using set comprehension + values() + sorted()
  
# initializing dictionary
test_dict = {'gfg' : [5, 6, 7, 8],
             'is' : [10, 11, 7, 5],
             'best' : [6, 12, 10, 8],
             'for' : [1, 2, 5]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Extract Unique values dictionary values
# Using set comprehension + values() + sorted()
res = list(sorted({ele for val in test_dict.values() for ele in val}))
  
# printing result 
print("The unique values list is : " + str(res)) 

Output :

The original dictionary is : {‘gfg’: [5, 6, 7, 8], ‘best’: [6, 12, 10, 8], ‘is’: [10, 11, 7, 5], ‘for’: [1, 2, 5]}
The unique values list is : [1, 2, 5, 6, 7, 8, 10, 11, 12]

Method #2 : Using chain() + sorted() + values()
This performs the task in similar way. The difference is that the task of set comprehension is performed using chain().

# Python3 code to demonstrate working of 
# Extract Unique values dictionary values
# Using chain() + sorted() + values()
from itertools import chain
  
# initializing dictionary
test_dict = {'gfg' : [5, 6, 7, 8],
             'is' : [10, 11, 7, 5],
             'best' : [6, 12, 10, 8],
             'for' : [1, 2, 5]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Extract Unique values dictionary values
# Using chain() + sorted() + values()
res = list(sorted(set(chain(*test_dict.values()))))
  
# printing result 
print("The unique values list is : " + str(res)) 

Output :

The original dictionary is : {‘gfg’: [5, 6, 7, 8], ‘best’: [6, 12, 10, 8], ‘is’: [10, 11, 7, 5], ‘for’: [1, 2, 5]}
The unique values list is : [1, 2, 5, 6, 7, 8, 10, 11, 12]

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