How to convert a string to an integer in Python

How to convert a string to an integer in Python.

Here's a step-by-step tutorial on how to convert a string to an integer in Python:

Step 1: Initialize a string variable

Let's start by initializing a string variable. This variable will hold the string value that we want to convert to an integer. For example, we can set the string variable num_str to the value "123".

num_str = "123"

Step 2: Use the int() function

To convert the string to an integer, we can use the int() function provided by Python. This function takes a string as an argument and returns an integer representation of that string.

num_int = int(num_str)

In this example, we pass the num_str variable as an argument to the int() function. The returned value is then assigned to the variable num_int.

Step 3: Print the integer value To verify that the string has been successfully converted to an integer, we can print the value of the num_int variable.

print(num_int)

This will output 123, which is the integer representation of the initial string "123".

Step 4: Handling invalid strings

If you try to convert a string that cannot be interpreted as an integer, a ValueError will be raised. For example, let's try to convert the string "abc" to an integer.

invalid_str = "abc"
invalid_int = int(invalid_str)

This code will raise a ValueError because the string "abc" cannot be converted to an integer. To handle this situation, you can use a try-except block to catch the ValueError and handle it accordingly.

try:
    invalid_int = int(invalid_str)
except ValueError:
    print("Invalid string format!")

By using a try-except block, if a ValueError is raised during the conversion, the code inside the except ValueError block will be executed. In this example, it will print the message "Invalid string format!".

That's it! You now know how to convert a string to an integer in Python using the int() function.