Python is a popular programming language used extensively for programming applications and websites. One of the essential functions in Python is to convert strings to integers. In this article, we will discuss the various ways to convert strings to integers in Python.

## Introduction

When we receive input from the user, it is generally in the form of a string. Performing mathematical operations with strings is not possible, so it is essential to convert them to integers before performing any math calculation. Python provides various built-in functions to convert strings to integers, making it easy for programmers to perform their operations.

## Four Ways to Convert String to Integer

In Python, there are four ways to convert strings to integers, and we will discuss each one in detail below.

### 1. Using int()

The int() function in Python is used to convert strings to integers. It takes one argument, which is the string to be converted. This function returns the converted integer value.

```
example_string = "1234"
convert_to_int = int(example_string)
print("The converted integer is:", convert_to_int)
```

The output of the above code will be “The converted integer is: 1234.”

### 2. Using the Numpy Library

Numpy is a Python library that is used to perform scientific operations. It includes a function called “numpy.astype” that can be used to convert strings to integers.

```
import numpy as np
example_string = "1234"
convert_to_int = np.astype(int, example_string)
print("The converted integer is:", convert_to_int)
```

The output of the above code will be “The converted integer is: 1234.”

### 3. Using the map() Function

The map() function is a Python built-in function that can be used to apply a function to every element in an iterable. In this case, we can use the map() function to convert each individual character in a string to its corresponding integer value using the int() function.

```
example_string = "1234"
mapped_list = map(int, example_string)
convert_to_int = list(mapped_list)
print("The converted integer is:", convert_to_int)
```

The output of the above code will be “The converted integer is: [1, 2, 3, 4].”

### 4. Using the ast.literal_eval() Function

The ast.literal_eval() function can be used to convert a string into its corresponding data type. It is generally used to evaluate strings that contain Python expressions. In this case, we can use ast.literal_eval() to convert a string to an integer.

```
import ast
example_string = "1234"
convert_to_int = ast.literal_eval(example_string)
print("The converted integer is:", convert_to_int)
```

The output of the above code will be “The converted integer is: 1234.”

## FAQs on String to int in Python

**Q1. Why do we need to convert strings to integers in Python?**

In Python, we generally receive input from users in the form of strings. It is not possible to perform mathematical operations on strings. So, we need to convert strings to integers before performing any calculations.

**Q2. Can we convert a string containing alphabets to an integer?**

No, it is not possible to convert a string containing alphabets to an integer.

**Q3. What is the difference between int() and ast.literal_eval()?**

The int() function is used to convert a string to an integer, while ast.literal_eval() is used to evaluate a string that contains a Python expression and returns the corresponding data type.

**Q4. Can we convert a float string to an integer?**

Yes, we can convert a float string to an integer using the int() function. However, it will only convert the integer part of the string and truncate the decimal part.

## Conclusion

Converting strings to integers is an essential task in Python, and there are various methods to do so. By using any of the above methods, we can easily convert a string to an integer and perform mathematical operations on it. Knowing how to do this is necessary for any beginner or experienced Python developer.