Get the first 2 digits of a number in JavaScript

In this tutorial, we will learn how to get the first 2 digits of a number in JavaScript.

Note: In JavaScript, strings are the sequence of characters, where the index of the first character is 0, the second character is 1, third character is 3 etc.

Getting the first 2 digits of a number

To get the first 2 digits of a number, convert the number to a string and use the built-in substring() method by passing the 0, 2 as an arguments to it. Then convert the string back to a number.

Where 0 is the start index, 2 is the end index which is excluded from the output.

Here is an example:

const id = 2345;

const firstTwoNumbers = String(id).substring(0, 2);
console.log(Number(firstTwoNumbers));

Output:

23

In the example above, we have passed 0, 2 as an arguments to the substring() method. so it begins the extraction at index 0 and extracts before the index 2 of a string.

The String() and Number() functions are used to convert the string to a number or vice versa.

Alternatively, we can also the slice() method in JavaScript, to access the first 2 digits of a number.

Here is an example:

const id = 2345;

const firstTwoNumbers = String(id).slice(0, 2);
console.log(Number(firstTwoNumbers));

Output:

23

The slice() method takes the two arguments, the first argument is start index and the second argument is end index then it returns a new string between the start index and end index (that is excluded from the output).

Also , we can use the regular expression to access the first 2 digits of a number.

Here is an example:

const id = 2345;

const firstTwoNumbers = String(id).match(/\d{2}/)[0];
console.log(Number(firstTwoNumbers)); // 23

The regular expression /\d{2}/, where d matches the numbers ranging from 0 to 9 and extracts the first 2 characters from the string.