Enumerate Function

The enumerate function is a built-in function in Python that simplifies looping through sequences (such as lists, tuples, or strings) by providing both the index and the value of each element in the sequence.

This makes it an efficient and clean way to access both the element and its position during iteration.

Basic Usage

The enumerate function returns a sequence of tuples, where each tuple contains:

1. The index of the element
2. The value of the element

Syntax:

enumerate(iterable, start=0)

• iterable: The sequence you want to iterate over (e.g., list, tuple, string)
• start (optional): Specifies the starting index (default is 0)

Example:

fruits = ['apple', 'banana', 'mango']
for index, fruit in enumerate(fruits):
    print(index, fruit)

Output:

0 apple
1 banana
2 mango

Customizing the Start Index

By default, the enumerate function starts the index at 0, but you can change the starting index by passing a value for the start parameter.

For example:

fruits = ['apple', 'banana', 'mango']
for index, fruit in enumerate(fruits, start=1):
    print(index, fruit)

Output:

1 apple
2 banana
3 mango

Common Use Cases

1. Numbered Output

When you need to print a sequence with numbered items:

fruits = ['apple', 'banana', 'mango']
for index, fruit in enumerate(fruits, start=1):
    print(f'{index}: {fruit}')

Output:

1: apple
2: banana
3: mango

2. Enumerating Tuples

The enumerate function works seamlessly with tuples.

colors = ('red', 'green', 'blue')
for index, color in enumerate(colors):
    print(index, color)

Output:

0 red
1 green
2 blue

3. Enumerating Strings

Strings are iterable, so you can use enumerate to loop over their characters.

s = 'hello'
for index, char in enumerate(s):
    print(index, char)

Output:

0 h
1 e
2 l
3 l
4 o

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