42 - Enumerate

Enumerate function in python

The enumerate function is a built-in function in Python that allows you to loop over a sequence (such as a list, tuple, or string) and get the index and value of each element in the sequence at the same time.

Here's a basic example of how it works:

# 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 output of this code will be:

0 apple
1 banana
2 mango

Here, index & fruits is being looped simultaneously & index=(previous value) +1 is added per loop.

Changing the start index

By default, the enumerate function starts the index at 0, but you can specify a different starting index by passing it as an argument to the enumerate function:

# 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): # now index is started from 1 instead of 0
    print(index, fruit)

This will output:

1 apple
2 banana
3 mango

The enumerate function is often used when you need to loop over a sequence and perform some action with both the index and value of each element. For example, you might use it to loop over a list of strings and print the index and value of each string in a formatted way:

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

This will output:

1: apple
2: banana
3: mango

In addition to lists, you can use the enumerate function with any other sequence type in Python, such as tuples and strings. Here's an example with a tuple:

# 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)

And here's an example with a string:

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

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