Python iter()

The iter() function is a built-in function in Python that returns an iterator from an iterable object, such as a list, tuple, string, or any object that implements the iterator protocol.

Syntax

iter(object, sentinel)

• object: A required argument that represents an iterable object such as a list, tuple, string, or any object that follows iterator or sequence protocol.
• sentinel: An optional argument that represents the end of the sequence.

Note: sentinel parameter is used to repeatedly call a function until a specific value is returned, which stops the iteration.

Example 1

This example demonstrates the use of the iter() function to create an iterator from a list and retrieve its elements one by one using the next() function:

# Example of iter() function without sentinel
fruits = ['apples', 'bananas', 'oranges']

# Creating an iterator from the list
my_iterator = iter(fruits)

print('Fruits:')
print(next(my_iterator))
print(next(my_iterator))
print(next(my_iterator))

Copy to clipboard
Copy to clipboard

The output would be:

Fruits:
apples
bananas
oranges

Copy to clipboard
Copy to clipboard

Example 2

This example demonstrates the use of the iter() function with a callable and a sentinel value, repeatedly calling the function until the sentinel is returned:

from functools import partial
import random

# iter() method with a callable and a sentinel argument os 7
def get_random_num(a, b):
  return random.randint(a, b)

another_iterator = iter(partial(get_random_num, 1, 10), 7)

print('\nNumbers: ')

# Loop will run till 7 is returned
for i in another_iterator:
  print(i)

Copy to clipboard
Copy to clipboard

The output would be:

Numbers:
2
8
1
6
9
5
8
2
9
5
2
9
4

Copy to clipboard
Copy to clipboard

Note: The output varies with each execution due to random integer generation, continuing until the sentinel value is encountered.

Codebyte Example

Visit us
Visit us
Hide code
Code
Output
Hide output
Copy to your clipboard
Copy Codebyte
Run