Javascript How to get first three characters of a string

Question

This may duplicate with previous topics but I can't find what I really need.

I want to get a first three characters of a string. For example:

var str = '012123';
console.info(str.substring(0,3));  //012

I want the output of this string '012' but I don't want to use subString or something similar to it because I need to use the original string for appending more characters '45'. With substring it will output 01245 but what I need is 01212345.

In this case, when it's a string, you'd be getting the characters, not necessarily digits. But I'm confused - you *are* getting the first 3 characters of the string. So what are you trying to do? — elzi, Oct 06 '16 at 02:52
`substring` will return a new string `012`, but `str` will still be equal to `012123`. `substring` will not change the contents of `str`. — Dave Cousineau, Oct 06 '16 at 02:52
Please [edit] your question to show how you are trying to use the results. Calling `.substring()` (or `.slice()` or `.substr()`) doesn't change the original string at all, it returns a *new* string. `str` doesn't change unless you explicitly overwrite it with `str = str.substring(0,3)`. — nnnnnn, Oct 06 '16 at 02:52
The above commenters are correct-- the method just returns what you want without changing the original string. So you can store the returned value in a variable like `strFirstThree = str.substring(0,3)` and still have access to `str` in its entirety. — Alexander Nied, Oct 06 '16 at 02:54

score 170 · Accepted Answer · edited May 22 '20 at 14:23

170

var str = '012123';
var strFirstThree = str.substring(0,3);

console.log(str); //shows '012123'
console.log(strFirstThree); // shows '012'

Now you have access to both.

edited May 22 '20 at 14:23

Flimm

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answered Oct 06 '16 at 02:56

Alexander Nied

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Flimm · Answer 2 · 2021-12-17T09:25:33.123

27

slice(begin, end) works on strings, as well as arrays. It returns a string representing the substring of the original string, from begin to end (end not included) where begin and end represent the index of characters in that string.

const string = "0123456789";
console.log(string.slice(0, 2)); // "01"
console.log(string.slice(0, 8)); // "01234567"
console.log(string.slice(3, 7)); // "3456"

Javascript How to get first three characters of a string

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