The enumerate() Function

The built-in enumerate() function wraps any iterable and yields each item together with its position index. No manual counter needed.

Use enumerate() in a for-loop to get both index and value:

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

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Output

The syntax for enumerate():

enumerate(iterable)
enumerate(iterable, start=n)  # start at n

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fruits = ['apple', 'banana']
for i, f in enumerate(fruits):
	print(i, f)

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You can convert enumerate() to a list to see all pairs at once:

colors = ['red', 'green', 'blue']
pairs = list(enumerate(colors))
print(pairs)

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Output

Pass start= to begin counting from a different number. Useful for 1-based rankings:

podium = ['Alice', 'Bob', 'Charlie']
for rank, name in enumerate(podium, start=1):
	print(rank, name)

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Output

pets = ['cat', 'dog', 'fish']
for i, p in enumerate(pets, start=1):
	print(i)
	break

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A common pattern: build a dict that maps each item to its index using enumerate().

Build a position lookup dict from a list:

cities = ['Paris', 'Tokyo', 'London']
position = {}
for i, city in enumerate(cities):
	position[city] = i
print(position['Tokyo'])

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Output

colors = ['red', 'green', 'blue']
d = {}
for i, c in enumerate(colors):
	d[c] = i
print(d['green'])

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enumerate() works inside list comprehensions too:

words = ['x', 'y', 'z']
pairs = [(i, w) for i, w in enumerate(words)]
print(pairs[2])

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Output

words = ['x', 'y', 'z']
pairs = [(i, w) for i, w in enumerate(words)]
print(pairs[2])

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items = ['a', 'b', 'c']
result = list(enumerate(items, start=10))
print(result[0])

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names = ['Ana', 'Ben', 'Cara']
for i, n in enumerate(names):
	if i == 1:
		print(n)

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