Enumerate Function

TL;DR

The enumerate() function adds automatic counters to any iterable, returning tuples of (index, value) pairs that make loops cleaner and more Pythonic.

Interesting!

You can start counting from any number using the start parameter, making enumerate perfect for creating numbered lists that don’t begin at zero.

Basic Enumeration

The simplest use case pairs each item with its index:

fruits = ['apple', 'banana', 'cherry']
for i, fruit in enumerate(fruits):
    print(f"{i}: {fruit}")
# Output:
# 0: apple
# 1: banana
# 2: cherry

Custom Starting Numbers

The start parameter lets you begin counting from any number:

# Create a numbered alphabet starting from 1
alphabet = [chr(x) for x in range(ord('a'), ord('z')+1)]
for num, letter in enumerate(alphabet, start=1):
    print(f"{num}: {letter}")
# Output: (1, 'a'), (2, 'b'), (3, 'c')... (26, 'z')

List Comprehensions with Enumerate

Enumerate works beautifully in list comprehensions and generator expressions:

# Create position-value pairs
data = ['red', 'green', 'blue']
indexed = [(i, color) for i, color in enumerate(data)]
# Result: [(0, 'red'), (1, 'green'), (2, 'blue')]

Why Use Enumerate

Instead of manually tracking indices with range(len()), enumerate provides a cleaner, more readable solution that’s less error-prone and more expressive about your intent.

Built-in Functions Control Flow Tools

Reference: enumerate() - Python Documentation