9/30/2017 - 2:30 PM

Find Numbers with Regular Expressions

We can use special selectors in Regular Expressions to select a particular type of value.

One such selector is the digit selector \d which is used to retrieve one digit (e.g. numbers 0 to 9) in a string.

In JavaScript, it is used like this: /\d/g.

Appending a plus sign (+) after the selector, e.g. /\d+/g, allows this regular expression to match one or more digits.

The trailing g is short for 'global', which allows this regular expression to find all matches rather than stop at the first match.

Instructions Use the \d selector to select the number of numbers in the string, allowing for the possibility of one or more digit.

// Setup
var testString = "There are 3 cats but 4 dogs.";

// Only change code below this line.

var expression = /\d+/g;  // Change this line

// Only change code above this line

// This code counts the matches of expression in testString
var digitCount = testString.match(expression).length;