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JavaScript \d and \D Metacharacters | RegEx Match Numbers or Digits
This post is published to provide information about two metacharacters used while working with JavaScript regular expressions. That are:
- The \d metacharacter
- The \D metacharacter
The \d metacharacter in JavaScript RegEx
The \d metacharacter is used when we need to match any digit from 0 to 9. For example:
<!DOCTYPE html>
<html>
<body>
<p id="xyz"></p>
<script>
let myString = "I got 100% marks in Cyber Security!";
let pattern = /\d/g;
document.getElementById("xyz").innerHTML = myString.match(pattern);
</script>
</body>
</html>In the above example, the following HTML code:
is an empty paragraph element with the ID "xyz". The ID attribute is used to uniquely identify a document element. Now, the following JavaScript statement:
let myString = "I got 100% marks in Cyber Security!";
declares a variable named "myString" and assigns it a string value of "I got 100% marks in Cyber Security!".
Then the following (second) JavaScript statement:
let pattern = /\d/g;
declares a variable named "pattern" and assigns it a regular expression value of /\d/g. This regular expression matches any digit character in a string. Finally, the following (last) JavaScript statement:
document.getElementById("xyz").innerHTML = myString.match(pattern);
uses the getElementById() method to get the HTML element with the ID "xyz" and sets its innerHTML property to the result of calling the match() method on the "myString" variable with the "pattern" regular expression. The match() method returns an array of all the digit characters in the "myString" variable.
Therefore, we can say \d does a similar job to [0-9].
Note: The match() method is used to match a string with or using a regular expression.
The \D metacharacter in JavaScript RegEx
Unlike \d, the \D metacharacter character is used to match any character other than digits (0-9). For example:
<!DOCTYPE html>
<html>
<body>
<p id="abc"></p>
<script>
let myString = "I got 100% marks in Cyber Security!";
let pattern = /\D/g;
document.getElementById("abc").innerHTML = myString.match(pattern);
</script>
</body>
</html>Therefore, we can say \D does a similar job to [^0-9].
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