Loop through Set
Because the set is an unordered collection, indexes cannot be used to access the elements of the set. To loop through sets, we need to take advantage of the loop statements. In this tutorial, we will discuss the various ways by which we can iterate over the elements of the set.
Using the for Loop
We can iterate over all the items in the set using the for loop. This is one of the easiest ways to iterate over the elements of the set. In the below example, we are using a for loop to iterate over the birds set.
birds = ("Parrot", "Crow", "Eagle")
for bird in birds:
print(bird)
Using the enumerate() method
We can use the enumerate method to iterate over the elements of the set. The enumerate method will return us the counter along with the original elements of the set. This counter will start from 0 and go until the number of elements minus on1. In the below example, the counter starts at zero and goes until 5-1, i.e. 4.
birds = ("Parrot", "Crow", "Eagle")
for n, bird in enumerate(birds):
print(n,"-",bird)
By Converting set to list
We can type cast the set to the list, i.e. use the list constructor to convert the set to the list. Now we have the list, we can iterate over the element of the list using any technique like for loop, for loop with range, etc.
birds_set = ("Parrot", "Crow", "Eagle")
birds_list = list(birds_set)
for n in range(len(birds_list)):
print(n, "-", birds_list[n])
Using comprehension and unpacking
List Comprehension can be used to iterate over the elements of the set. Here, the asterisk can be used to unpack the elements of the list.
We can use the print statement in the comprehension itself to print the elements of the set there. As shown in the example number three below.
birds_set = ("Parrot", "Crow", "Eagle")
birds = list(bird for bird in birds_set)
print(*birds)
Converting to a list using the square brackets [].
birds_set = ("Parrot", "Crow", "Eagle")
birds = [bird for bird in birds_set]
print(*birds)
Directly printing elements of the set.
birds_set = ("Parrot", "Crow", "Eagle")
birds = [print(bird) for bird in birds_set]
Using the iter() funciton
In Python, the iter() function is a built-in function that is used to obtain an iterator from an object. The iter() function takes an iterable object (like list, tuple, set, etc.) as an argument and returns an iterator for that object.
The iter() function is used in combination with the next() function. The next() function is used to retrieve the next element from an iterator. In the below example, we are using the iter() function to create the iterator of the numbers, and next is used to fetch the next element.
When the next() reaches the end of the iterator, it raises a StopIteration error, to catch that error try-except block is used.
birds_set = ("Parrot", "Crow", "Eagle")
# Creating an iterator object
iterator = iter(birds_set)
# printing elements of set
# The next function is retrieving elements
try:
while True:
item = next(iterator)
print(item)
except StopIteration:
pass
Using the zip() function
The zip() function in Python is a built-in function that allows us to combine elements from multiple iterables (such as lists, tuples, sets, etc.) into tuples. It pairs up the elements of the input iterables element-wise, creating an iterator of tuples. The i-th tuple contains the i-th elements from each of the input iterables.
numbers = (24, 25, 26)
characters = ('x', 'y', 'z')
# zip() to iterate over both the sets
for i, j in zip(numbers, characters):
print(i, "-", j)
