How to limit number of digits in regex-CodePudding

I'm using match to return only the numbers from the input. I need to limit the number of digits entered to 2. How can I do this?

const numbers = input.match(/[0-9] /g);

CodePudding user response：

Maybe you can use the attribut maxlength="2" for your imput

CodePudding user response：

We can match on the regex pattern ^[0-9]{1,2}:

var input = "12345";
const numbers = input.match(/^[0-9]{1,2}/);
console.log(input   " => "   numbers);

Note that we use ^[0-9]{1,2} rather than ^[0-9]{2} because perhaps the user only might enter a single digit.

CodePudding user response：

The simplest way to make it two numbers it to write is as two numbers

const numbers = input.match(/[0-9][0-9]/g);

Snother way is to write it as numbers with count of two

const numbers = input.match(/[0-9]{2}/g);

maybe you need to allow entering 1 number though

const numbers = input.match(/[0-9][0-9]?/g);
const numbers = input.match(/[0-9]|[0-9][0-9]/g);
const numbers = input.match(/[0-9]{1,2}/g);

CodePudding user response：

const input = "1234567890";
const regex = /^\d{2}$/;
const isTwoDigits = regex.test(input);

if (isTwoDigits) {
  console.log("The input contains exactly 2 digits");
} else {
  console.log("The input does not contain exactly 2 digits");
}

CodePudding user response：

This would be your regex:

const numbers = input.match(/[0-9]{1,2}/);

For simpler writing of regexes, I recommend using https://regex101.com as there is a real time tester and complete cheatsheet with examples.