trying to understand what this regex means

Question

Trying to understand what the below regex means.

/^[0-9]{2,3}[- ]{0,1}[0-9]{3}[- ]{0,1}[0-9]{3}$/

Sorry not exactly a coding question.

Means the same as this `^\d{2,3}(?:[- ]?\d{3}){2}$` – Jun 27 '19 at 00:05 — , Jun 27 '19 at 00:05

score 2 · Accepted Answer · answered Jun 27 '19 at 00:18

Let's break this regex into a few different parts:

^: asserts position at start of the string
[0-9]{2,3}: Match a number between 0 and 9, between 2 and 3 times
[- ]{0,1} Matches a dash between zero and one times (Optional dash)
[0-9]{3}: Match a number between 0 and 9, exactly 3 times
[- ]{0,1} Matches a dash between zero and one times (Optional dash)
[0-9]{3}: Match a number between 0 and 9, exactly 3 times
$: asserts position at the end of the string, or before the line terminator right at the end of the string (if any)

Here are a few strings that would pass this regex:

123-123-123
123123123
12-123-123
12123123

Here's a good resource to learn/test regexes: regex101.com

score 1 · Answer 2 · answered Jun 27 '19 at 00:03

1

It matches two or three digits followed by (optionally) a dash or space, then 3 digits, again optional dash or space and 3 digits. It seems to try to match a telephone number written in different formats.

answered Jun 27 '19 at 00:03

jacalvo

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trying to understand what this regex means

2 Answers2