Require true if only one pair of outer parenthesis is present (using Regex)

Question

var reg=/[\(\d{3}\)]/g;
(reg).test(str); //

the above code is true for any number of parenthesis str="(((555)))", str="((555))". I want true only when there is only one pair of parenthesis str="(555)" and for any other string it should be false;

Do you mean `var reg=/^$\d{3}$$/`? Match a string that starts with `(`, 3 digits, and then ends with `)`? — Wiktor Stribiżew, Nov 27 '17 at 14:24
@WiktorStribiżew starts with (,then 3 digits and then ) and can't ever have any surrounding characters! — Md Sifatul Islam, Nov 27 '17 at 14:34

hunteke · Accepted Answer · 2017-11-27T15:35:46.583

0

It looks like you are unclear on the character class operator. For what you have asked, you want to anchor at the beginning (^) and end ($) of the string, and you want to find a parenthesis ($) followed by 3 digits (\d{3} or \d\d\d) followed by a final parenthesis ($). Altogether:

var reg = /^\(\d{3}\)$/;

You were close, just needed to swap the brackets with the anchors.

edited Nov 27 '17 at 15:35

answered Nov 27 '17 at 14:30

hunteke

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More, you do not even need `g` here. – Wiktor Stribiżew Nov 27 '17 at 14:37
@WiktorStribiżew Good point. I must have copy pasted! I'll just fix that ... – hunteke Nov 27 '17 at 15:35

Require true if only one pair of outer parenthesis is present (using Regex)

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