# Use map() to convert strings to integers in a Python list

Last updated: Jun 16, 2022

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## Use map() to convert strings to integers in a Python list#

To use the `map()` function to convert a list of strings to a list of integers:

1. Pass the `int()` class and the list to the `map()` function.
2. The `map()` function will pass each item of the list to the `int()` class.
3. The new list will only contain integer values.
main.py
```Copied!```my_list = ['1', '2', '3', '4']

new_list = list(map(int, my_list))

print(new_list) # 👉️ [1, 2, 3, 4]
``````

The map() function takes a function and an iterable as arguments and calls the function with each item of the iterable.

We used the `int` class to convert the strings in the list to integers.

main.py
```Copied!```print(int('1')) # 👉️ 1
print(int('2')) # 👉️ 2
``````

The int class returns an integer object constructed from the provided number or string argument.

The constructor returns `0` if no arguments are given.

Alternatively, you can use a list comprehension to convert a list of strings to a list of integers.

main.py
```Copied!```my_list = ['1', '2', '3', '4']

new_list = [int(item) for item in my_list]

print(new_list) # 👉️ [1, 2, 3, 4]
``````
List comprehensions are used to perform some operation for every element, or select a subset of elements that meet a condition.

In the example, we call the `int()` class with each item in the list and return the result.

If you want to convert the items of the list in place instead of creating a new list with integers, use a `for` loop.

main.py
```Copied!```my_list = ['1', '2', '3', '4']

for index, item in enumerate(my_list):
my_list[index] = int(item)

print(my_list)  # 👉️ [1, 2, 3, 4]
``````

The enumerate function takes an iterable and returns an enumerate object containing tuples where the first element is the index, and the second - the item.

On each iteration, we use the index to update the value of the list item to an integer.

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