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))

The output would be:

Fruits:
apples
bananas
oranges

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)

The output would be:

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

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

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