Enumerate Function in Python with Examples

Have you ever written index = 0 above a loop, incremented it at the bottom, and then wondered what happens when the loop gets a continue? That counter works, but it gives you another piece of state to maintain.

enumerate() puts the position beside the item for you. It accepts an iterable and returns an iterator that produces pairs such as (0, "apple"). Python creates each pair as the loop requests it, so you can use it without building a second list first.

The loop you actually want

The built-in function works with lists, tuples, strings, and other iterable objects:

# Loop over a list and print the index and value of each element
fruits = ['apple', 'banana', 'mango']
for index, fruit in enumerate(fruits):
    print(index, fruit)

The loop unpacks each pair into index and fruit. The output is:

0 apple
1 banana
2 mango

If you want to inspect every pair at once, convert the iterator to a list:

fruits = ['apple', 'banana', 'mango']
print(list(enumerate(fruits)))

That prints [(0, 'apple'), (1, 'banana'), (2, 'mango')]. In ordinary loops, do not add list() just to make the code look familiar. The loop already consumes the iterator one pair at a time, which avoids storing another collection.

The same pattern is handy when you need to replace or inspect one item. For example, this prints a numbered warning only for a missing value:

statuses = ["ok", "missing", "ok"]
for position, status in enumerate(statuses, start=1):
    if status == "missing":
        print(f"Row {position} needs attention")

The output is Row 2 needs attention. Notice that the list remains unchanged. enumerate() reports positions; it does not edit the iterable for you.

This is usually clearer than indexing with range(len(fruits)):

for index in range(len(fruits)):
    print(index, fruits[index])

The indexed version is not always wrong. It makes sense when you need to compare neighboring positions, assign back into a mutable list, or use the same index for several sequences. If you only need the value and its position, enumerate() says that directly and gives you fewer moving parts.

Starting from one instead of zero

Python uses zero-based indexes by default, so the first item gets index 0. That is useful when the number is an index into another sequence. If you are showing positions to a person, starting at 1 usually reads better. Pass the starting value with start:

# Loop over a list and print the index (starting at 1) and value of each element
fruits = ['apple', 'banana', 'mango']
for index, fruit in enumerate(fruits, start=1):
    print(index, fruit)

Now the output is:

1 apple
2 banana
3 mango

You can format the position in the loop without changing the original list:

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

The output is:

1: apple
2: banana
3: mango

Lists are not special

A tuple works the same way:

# Loop over a tuple and print the index and value of each element
colors = ('red', 'green', 'blue')
for index, color in enumerate(colors):
    print(index, color)

Strings are iterable too, so enumerate() can give you each character and its position:

# Loop over a string and print the index and value of each character
s = 'hello'
for index, c in enumerate(s):
    print(index, c)

You can pass a generator as well. That is where the lazy behavior becomes more useful:

def read_numbers():
    for number in range(3):
        yield number * 10
 
for index, number in enumerate(read_numbers(), start=1):
    print(index, number)

The loop prints 1 0, 2 10, and 3 20 without asking the generator for every value in advance.

You can enumerate dictionary items too. enumerate() supplies the position, while .items() supplies the key and value:

prices = {"tea": 20, "coffee": 30}
for position, (name, price) in enumerate(prices.items(), start=1):
    print(position, name, price)

The nested unpacking may look busy the first time you see it, but the names tell you what each value means. A separate counter would add no useful information here.

There are two easy mistakes. First, start=1 changes the number reported by enumerate(), not the indexes stored in your list. Second, the position is not a permanent ID. If you remove items while iterating, later positions describe the current pass through the data. Changing a collection during a loop can create its own problems, so build a new collection when you need to filter or reorder values.

For a normal read-only loop, enumerate() is the cleanest answer whenever you need an item and its position. It is small, readable, and removes the counter bug before you have to debug it.

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