How to Convert a String to an Integer in Python

Python is a powerful programming language largely due to its flexibility. One such evidence of that flexibility is Python’s ability to easily convert data from one type to another. In this tutorial, we’ll walk you through how to convert a string to an integer in Python.

Understanding Strings and Integers

Before delving into the conversion process, it’s important to understand what a string and integer are. In Python, a string is a sequence of characters enclosed either in single quotation marks, double quotation marks, or even triple quotes. On the other hand, an integer in Python is a whole number without a decimal.

Method to Convert String to Integer

The Python built-in function int() is used to convert a string into an integer.

Here is the basic format of how to use it:

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number = int(string)

Convert a String to an Integer: An Example

Let’s suppose we have a string ‘123’ and we want to convert it into an integer.

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str_num = '123'
int_num = int(str_num)
print(int_num)

The output will be:

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123

Handling ValueError

But you should keep in mind that not every string can be converted to an integer. If the string does not represent a valid integer, Python will raise a ValueError exception. So it is a good practice to handle this exception while converting a string to an integer.

Here’s how to handle it:

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str_num = '123abc'
try:
   int_num = int(str_num)
   print(int_num)
except ValueError:
   print('The string cannot be converted to an integer')

Full Code

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str_num1 = '123'
str_num2 = '123abc'
 
int_num1 = int(str_num1)
 
try:
   int_num2 = int(str_num2)
   print(int_num2)
except ValueError:
   print('The string cannot be converted to an integer')
 
print(int_num1)

The outputs are:

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123
The string cannot be converted to an integer

Conclusion

Converting strings to integers in Python is easy and straightforward using the int() function. However, remember to always handle possible errors to make your code robust and reliable. Be careful when converting, as not all strings can be appropriately formatted into integers.

Such string-to-integer conversion is a fundamental part of data manipulation in Python programming.