regex_numbers.js

/*
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. Living in 10 houses";

// 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;

console.log("Regex find number: ", digitCount);