union(): merging Sets in Python

The union() method merges as many sets as you want and returns a new set as a result.

The items in the new set are unique, meaning no repetitions.

In the example below both sets together should equal 6 items, but ‘bmw’ is present in both of them, so only one remains and the resulting set has only 5 items.

car_brands_set_one = {'bmw', 'mclaren', 'ferrari'}

car_brands_set_two = {'honda', 'bmw', 'ford'}

car_brands_set_merged = car_brands_set_one.union(car_brands_set_two)

print(car_brands_set_merged)

{'bmw', 'mclaren', 'ford', 'honda', 'ferrari'}

When merging more than two sets, they have to be separated by commas.

car_brands_set_one = {'bmw', 'mclaren', 'ferrari'}

car_brands_set_two = {'honda', 'bmw', 'ford'}

car_brands_set_three = {'mclaren', 'toyota', 'jeep'}

car_brands_set_four = {'suzuki', 'ford', 'hyundai'}

car_brands_set_merged = car_brands_set_one.union(
car_brands_set_two, 
car_brands_set_three, 
car_brands_set_four
)

print(car_brands_set_merged)

{'bmw', 'hyundai', 'honda', 
'jeep', 'suzuki', 'toyota', 
'mclaren', 'ford', 'ferrari'}

To learn more about Sets, read this post Python Set: a quick reference