Converting all Strings in a List to Integers - Python

Converting all Strings in a List to Integers - Python

Last Updated : 18 Apr, 2025

We are given a list of strings containing numbers and our task is to convert these strings into integers. For example, if the input list is ["1", "2", "3"] the output should be [1, 2, 3]. Note: If our list contains elements that cannot be converted into integers such as alphabetic characters, strings or special symbols, trying to convert them using int() will raise a ValueError or Invalid Literal Error. Let's discuss various ways to convert all string elements in a list to integers in Python.

Using map()

map() function applies a given function to all elements in an iterable. Here, we use map(int, a) to convert each string in the list to an integer.

Python

a = ['2', '4', '6', '8']

b = list(map(int, a))
print(b)

Output

[2, 4, 6, 8]

Explanation:

map(int, a) applies the int() function to every item in the list 'a'.
list(map(int, a)) converts the result of map() into a list.

Using list comprehension

List comprehension provides a more Pythonic and concise way to convert a list of strings to integers as it combines the conversion and iteration into a single line of code.

Python

a = ['2', '4', '6', '8']

b = [int(item) for item in a]
print(b)

Output

[2, 4, 6, 8]

Explanation:

int(item) converts each string in the list to an integer.
[int(item) for item in a] this list comprehension goes through each element (item) of 'a', applies int() and collects the results in a new list.

Using a loop

In this approach we iterate over the list using a loop (for loop) and convert each string to an integer using the int() function.

Python

a = ['2', '4', '6', '8']

for i in range(len(a)):
  
    a[i] = int(a[i])

print(a)

Output

[2, 4, 6, 8]

Explanation:

for i in range(len(a)) iterates over the indices of the list a.
a[i] = int(a[i]) converts each string at index i to an integer and updates the list in place.

Converting all Strings in a List to Integers - Python

manjeet_04

Improve

Article Tags :

Practice Tags :

Similar Reads

Convert integer to string in Python

In this article, weâ€™ll explore different methods for converting an integer to a string in Python. The most straightforward approach is using the str() function.Using str() Functionstr() function is the simplest and most commonly used method to convert an integer to a string.Pythonn = 42 s = str(n) p

Convert string to a list in Python

Our task is to Convert string to a list in Python. Whether we need to break a string into characters or words, there are multiple efficient methods to achieve this. In this article, we'll explore these conversion techniques with simple examples. The most common way to convert a string into a list is

Python - Converting list string to dictionary

Converting a list string to a dictionary in Python involves mapping elements from the list to key-value pairs. A common approach is pairing consecutive elements, where one element becomes the key and the next becomes the value. This results in a dictionary where each pair is represented as a key-val

Convert String to Int in Python

In Python, converting a string to an integer is important for performing mathematical operations, processing user input and efficiently handling data. This article will explore different ways to perform this conversion, including error handling and other method to validate input string during conver

How to convert string to integer in Python?

In Python, a string can be converted into an integer using the following methods : Method 1: Using built-in int() function: If your string contains a decimal integer and you wish to convert it into an int, in that case, pass your string to int() function and it will convert your string into an equiv

Python Hex String to Integer List

Hexadecimal strings are commonly encountered when working with low-level programming, networking, or cryptographic applications. In Python, converting a hex string to an integer array or list is a frequent task. In this article, we'll explore some different methods to achieve this conversion. Hex St

Convert String to Long in Python

Python defines type conversion functions to directly convert one data type to another. This article is aimed at providing information about converting a string to long. Converting String to long A long is an integer type value that has unlimited length. By converting a string into long we are transl

Python - Convert list of string to list of list

In Python, we often encounter scenarios where we might have a list of strings where each string represents a series of comma-separated values, and we want to break these strings into smaller, more manageable lists. In this article, we will explore multiple methods to achieve this. Using List Compreh

Convert Object to String in Python

Python provides built-in type conversion functions to easily transform one data type into another. This article explores the process of converting objects into strings which is a basic aspect of Python programming.Since every element in Python is an object, we can use the built-in str() and repr() m

Check If String is Integer in Python

In this article, we will explore different possible ways through which we can check if a string is an integer or not. We will explore different methods and see how each method works with a clear understanding.Example:Input2 : "geeksforgeeks"Output2 : geeksforgeeks is not an IntigerExplanation : "gee