Extract Number from String in JavaScript

When working with text data in JavaScript, it’s common to encounter situations where you need to extract numbers from a string. This could be for processing user input, parsing data from an external source, or any number of other use cases. Fortunately, JavaScript provides several methods for extracting numbers from a string. In this article, we’ll explore some common approaches for extract numbers from a string in JavaScript:

Using regular expressions

To extract a number from a string in JavaScript, we can use the ‘match()’ method of a string object along with a regular expression. The regular expression is ‘/\d+/g’, matches one or more digits (\d+) globally (g) in the string. The match() method returns an array of all matches found in the string.

const string = "Jo3hn2310";
const numbers = string.match(/\d+/g);
console.log(numbers);

// Output : ['3', '2310']

Using the parseFloat or parseInt functions:

We can also use parseFloat() or parseInt() method with regular expression. The parseFloat and parseInt functions are built-in functions for parsing strings and extracting numeric values. If you want to return a floating-point number from a string you can use parseFloat(). If you want to return an integer number from a string, you can use parseInt(). In this approach, we first use a regular expression to extract the number, and then we pass the extracted string to either ‘parseFloat()’ or ‘parseInt()’ to get the numeric value.

const str = "My balance is $10.5";
const bal= parseFloat(str.match(/\d+\.\d+/));
console.log(bal);

// Output: 10.5

const str = "The price of apple is $5";
const price = parseInt(str.match(/\d+/g));
console.log(price);

// Output: 5

Conclusion

These are just a few examples of extracting numbers from a string in JavaScript. The best approach depends on the specific requirements of your application.