Check if string ends with

Question

I want to check if a string ends with

- v{number}

So for example

hello world           false
hello world - v2      true
hello world - v       false
hello world - v88     true

Not entirely sure how to go about doing this RegEx.

var str = 'hello world - v1';
var patt = new RegExp("/^ - v\d*$/");
var res = patt.test(str);
console.log(res);

How could I fix the above RegEx?

You linked to a page in my answer but now your comment is gone. Note I updated explaining no need for `/` and double escaping of `\d`. — fedorqui, Jul 07 '16 at 09:53
@praveen Have you read the question and answer on that page before marking duplicate? It is non-sense. In that case length of end with is constant and ends with a particular character, here length is variable, like 'hello world - v1234567890'. — Harish Kumar, Jul 07 '16 at 10:20

score 5 · Accepted Answer · edited May 23 '17 at 11:58

5

Just use this without checking anything else in the beginning

- v\d+$

This way you make sure it ends with - v followed by at least one digit. See it live in https://regex101.com/r/pB6vP5/1

Then, your expression needs to be:

var patt = new RegExp("- v\\d+$");

As stated by anubhava in another answer:

No need for /
Requires double escaping for \d.

var str = 'hello world - v15';
var patt = new RegExp("- v\\d+$");
var res = patt.test(str);
console.log(res);

edited May 23 '17 at 11:58

Community

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answered Jul 07 '16 at 09:44

fedorqui

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What's the `m` flag? You need to include that as well in the answer. – Praveen Kumar Purushothaman Jul 07 '16 at 09:45
@PraveenKumar I don't know why you deleted your answer, the logic seemed right to me. – Tim Biegeleisen Jul 07 '16 at 09:45
1

@PraveenKumar it is for multi-line matching. This way you can include different lines in regex101.com and all of them are matched individually. – fedorqui Jul 07 '16 at 09:46
1

Ah, now I understood why my answer didn't work, @TimBiegeleisen! – Praveen Kumar Purushothaman Jul 07 '16 at 10:21
@PraveenKumar Yes, but do you need double escaping with `test()`? I'm not sure about that. – Tim Biegeleisen Jul 07 '16 at 10:23
@TimBiegeleisen Yes! We need to. The `RegExp` value. – Praveen Kumar Purushothaman Jul 07 '16 at 10:26
@fedorqui Upvoted to apologize for defacing your answer via verbose comments ^ ^ – Tim Biegeleisen Jul 07 '16 at 10:27
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@TimBiegeleisen no need to apologize neither need to upvote for off-topic reasons : ) I learnt a lot from both the comment by anubhava few days ago and now your discussion with Praveen! – fedorqui Jul 07 '16 at 10:29

score 0 · Answer 2 · answered Jan 27 '20 at 00:57

This is a solution that achieves the same results without a Regex. Worth giving it a try.

function stringEndsWithVersionNum(string) 
{
    var parts   = string.split('- v');
    if(parts[0] !== string) //if the string has '- v' in it
    {
        var number = parts[parts.length -1].trim();//get the string after -v
        return !isNaN(number) && number.length > 0;//if string is number, return true. Otherwise false.
    }
    return false; 
}

Please use like so:

stringEndsWithVersionNum('hello world - v32')//returns true
stringEndsWithVersionNum('hello world - v'); //returns false 
stringEndsWithVersionNum('hello world');     //returns false

Check if string ends with

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