Table of Contents
In this tutorial, we will learn about the Python set() function with the help of examples.
The set()
function creates a set in Python.
Example
list_numbers = [1, 2, 3, 4, 2, 5] # create set from list numbers_set = set(list_numbers) print(numbers_set) # Output: {1, 2, 3, 4, 5}
1. set() Syntax
The syntax of set()
is:
set(iterable)
Recommended Reading: Python sets
2. set() Parameters
set()
takes a single optional parameter:
- iterable (optional) – a sequence (string, tuple, etc.) or collection (set, dictionary, etc.) or an iterator object to be converted into a set.
3. set() Return Value
set()
returns:
- an empty set if no parameters are passed
- a set constructed from the given iterable parameter
4. Example 1: Create sets from string, tuple, list, and range
# empty set print(set()) # from string print(set('Python')) # from tuple print(set(('a', 'e', 'i', 'o', 'u'))) # from list print(set(['a', 'e', 'i', 'o', 'u'])) # from range print(set(range(5)))
Output
set() {'P', 'o', 't', 'n', 'y', 'h'} {'a', 'o', 'e', 'u', 'i'} {'a', 'o', 'e', 'u', 'i'} {0, 1, 2, 3, 4}
Note: We cannot create empty sets using
{ }
syntax as it creates an empty dictionary. To create an empty set, we useset()
.
5. Example 2: Create sets from another set, dictionary and frozen set
# from set print(set({'a', 'e', 'i', 'o', 'u'})) # from dictionary print(set({'a':1, 'e': 2, 'i':3, 'o':4, 'u':5})) # from frozen set frozen_set = frozenset(('a', 'e', 'i', 'o', 'u')) print(set(frozen_set))
Output
{'a', 'o', 'i', 'e', 'u'} {'a', 'o', 'i', 'e', 'u'} {'a', 'o', 'e', 'u', 'i'}
6. Example 3: Create set() for a custom iterable object
class PrintNumber: def __init__(self, max): self.max = max def __iter__(self): self.num = 0 return self def __next__(self): if(self.num >= self.max): raise StopIteration self.num += 1 return self.num # print_num is an iterable print_num = PrintNumber(5) # creating a set print(set(print_num))
Output
{1, 2, 3, 4, 5}
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