Set from Dictionary Values - Python

Last Updated : 22 Jan, 2025

The task is to extract unique values from a dictionary and convert them into a set. In Python, sets are unordered collections that automatically eliminate duplicates. The goal is to extract all the values from the dictionary and store them in a set.

For example, given a dictionary like d = {'A': 4, 'B': 3, 'C': 7, 'D': 4}, the goal is to retrieve all values from the dictionary and store them in a set, resulting in {3, 4, 7}.

Using values()

This method is considered the most efficient because the values() method of the dictionary returns a view object that directly gives access to the dictionary’s values. Converting this view to a set using the set() allows us to easily get all unique values without the need for additional iterations.

Python

d = {'Gfg': 4, 'is': 3, 'best': 7, 'for': 3, 'geek': 4}

res = set(d.values())
print(res)

Output

{3, 4, 7}

Explanation:

d.values() returns a view of the dictionary’s values ([4, 3, 7, 3, 4]).
set() converts these values into a set and removing duplicates and resulting in {4, 3, 7}.

Table of Content

Using Set Comprehension
Using map()
Using for loop

Using Set Comprehension

Set comprehension is another efficient method that involves iterating over the dictionary’s values and adding them to a set in a single line. This method is almost as efficient as set(d.values()) but requires an explicit iteration over the values, making it slightly less optimal for very large dictionaries.

Python

d = {'Gfg': 4, 'is': 3, 'best': 7, 'for': 3, 'geek': 4}

res = {value for value in d.values()}
print(res)

Output

{3, 4, 7}

Explanation: set comprehension iterate over the dictionary’s values and directly create a set and removes duplicates.

Using map()

map() applies a given function (e.g., lambda x: x) to each element in the dictionary’s values and then converts the result into a set. It’s more complex than other methods but useful when transformations are needed before adding values to the set.

Python

d = {'Gfg': 4, 'is': 3, 'best': 7, 'for': 3, 'geek': 4}

res = set(map(lambda x: x, d.values()))
print(res)

Output

{3, 4, 7}

Explanation:

d.values() retrieves the dictionary's values ([4, 3, 7, 3, 4]).
map() applies an identity lambda (lambda x: x) to each value and resulting in the same values.
set() removes duplicates, resulting in the set {4, 3, 7}.

Using for loop

Manually iterating over the dictionary’s values and adding them to a set is valid but less efficient than using built-in methods like set(d.values()) or set comprehension due to loop overhead.

Python

d = {'Gfg': 4, 'is': 3, 'best': 7, 'for': 3, 'geek': 4}
res = set()

for value in d.values():
    res.add(value)
print(res)

Output

{3, 4, 7}

Explanation:

for loop iterates over the values of the dictionary d using d.values().
For each value in the dictionary d it is added to the set res using the add() method.