How to turn string into int Python?

Converting Strings to Integers in Python

Python provides several ways to convert strings to integers. In this article, we will explore the most common methods and provide examples to help you understand how to do it.

Method 1: Using the int() Function

The int() function is a built-in Python function that converts a string to an integer. Here’s how you can use it:

• Syntax: int(string)
• Example:

  print(int("123"))  # Output: 123
  
  print(int("abc"))  # Output: 0

Method 2: Using the str() Function and int() Conversion

You can also use the str() function to convert a string to an integer. However, this method is not as efficient as the int() function.

• Syntax: str(string).replace(" ", "")
• Example:

  print(str("123").replace(" ", ""))  # Output: 123
  
  print(str("abc").replace(" ", ""))  # Output: 0

Method 3: Using Regular Expressions

Regular expressions are a powerful tool in Python that can be used to convert strings to integers. Here’s how you can use them:

• Syntax: re.search(r"d+", string)
• Example:

  
  
  import re

string = "123abc"
match = re.search(r"d+", string)
if match:
print(match.group()) # Output: 123

### **Method 4: Using the `eval()` Function**



The `eval()` function is a built-in Python function that evaluates a string as a Python expression. However, this method is not recommended as it can pose a security risk if you're planning to execute user-supplied input.



*   **Syntax:** `eval(string)`

*   **Example:**

    ```python

import eval



string = "123"

print(eval(string))  # Output: 123

Method 5: Using the ast.literal_eval() Function

The ast.literal_eval() function is a safer alternative to the eval() function. It only evaluates literals, which means it won’t execute any code.

• Syntax: ast.literal_eval(string)
• Example:

  
  
  import ast

string = "123"
print(ast.literal_eval(string)) # Output: 123

### **Method 6: Using the `numpy.int64()` Function**



The `numpy.int64()` function is a NumPy function that converts a string to an integer. Here's how you can use it:



*   **Syntax:** `numpy.int64(string)`

*   **Example:**

    ```python

import numpy as np



string = "123"

print(np.int64(string))  # Output: 123

Method 7: Using the pint Library

The pint library is a Python library that provides a simple way to convert strings to integers. Here’s how you can use it:

• Installation: pip install pint
• Example:

  
  
  import pint

string = "123"
print(pint.Int32(string)) # Output: 123

### **Conclusion**



In conclusion, there are several ways to convert strings to integers in Python. The `int()` function is the most common method, but it's not the most efficient. Regular expressions and the `eval()` function are not recommended as they can pose a security risk. The `ast.literal_eval()` function is a safer alternative, but it's not as efficient as the `int()` function. The `numpy.int64()` function is a NumPy function that converts a string to an integer. Finally, the `pint` library is a Python library that provides a simple way to convert strings to integers.



### **Code Snippets**



Here are some code snippets to help you understand how to convert strings to integers:



*   **Method 1: Using the `int()` Function**

    ```python

print(int("123"))  # Output: 123

print(int("abc"))  # Output: 0

• Method 2: Using the str() Function and int() Conversion

  print(str("123").replace(" ", ""))  # Output: 123
  
  print(str("abc").replace(" ", ""))  # Output: 0

• Method 3: Using Regular Expressions

  
  
  import re

string = "123abc"
match = re.search(r"d+", string)
if match:
print(match.group()) # Output: 123

*   **Method 4: Using the `eval()` Function**

    ```python

import eval



string = "123"

print(eval(string))  # Output: 123

• Method 5: Using the ast.literal_eval() Function

  
  
  import ast

string = "123"
print(ast.literal_eval(string)) # Output: 123

*   **Method 6: Using the `numpy.int64()` Function**

    ```python

import numpy as np



string = "123"

print(np.int64(string))  # Output: 123

• Method 7: Using the pint Library

  
  
  import pint

string = "123"
print(pint.Int32(string)) # Output: 123

### **Best Practices**



Here are some best practices to keep in mind when converting strings to integers:



*   **Use the `int()` Function**: The `int()` function is the most common method for converting strings to integers.

*   **Avoid Using `eval()`**: The `eval()` function can pose a security risk if you're planning to execute user-supplied input.

*   **Use Regular Expressions Safely**: Regular expressions can be used to convert strings to integers, but they should be used with caution to avoid security risks.

*   **Use the `ast.literal_eval()` Function Safely**: The `ast.literal_eval()` function is a safer alternative to the `eval()` function, but it should be used with caution to avoid security risks.

*   **Use the `numpy.int64()` Function Safely**: The `numpy.int64()` function is a NumPy function that converts a string to an integer, but it should be used with caution to avoid security risks.