What does ''-' mean in ^[A-Z]+[a-zA-Z''-'\s]*$?

Question

I found a regex ^[A-Z]+[a-zA-Z''-'\s]*$ from this tutorial and does not understand the meaning of ''-'. What does it mean?

Edit

After reading the comments given to this question and the corresponding answer or deleted answer, now I know that this question must be deleted because this problem is about typo presented in the tutorial.

`'-'` has no sense at all. It means `'`to `'`...Especially with the `'` before it it's even more useless! — csabinho, Jan 06 '18 at 08:03
No, it means ASCII code from `"` to `'`. Which might be quite confusing... — csabinho, Jan 06 '18 at 08:07
@PetervanderHeijden The question is valid. The OP asks about an unclear (and very probably useless) part in a regex he otherwise understands. — Tomalak, Jan 06 '18 at 08:26
@Tomalak The linked (duplicate) question deals with exactly the same pattern https://stackoverflow.com/a/11854572/1190388 — hjpotter92, Jan 06 '18 at 08:31
Goto Regex101.com, paste your regex there, it will give you a very nice explanation — Sunil, Jan 06 '18 at 08:38
@Artificial: Personally, I think the question is fine. The fact that it has been asked and answered before is not a problem. Your question even adds some new information: the source of the odd regex. The two answers that were deleted were completely irrelevant to your question, so that's entirely appropriate. — Nisse Engström, Jan 07 '18 at 01:06

score 2 · Accepted Answer · answered Jan 06 '18 at 08:36

2

When we leave out the other, well-understood parts of the character class, this remains: [''-'].

This construct has no use. It translates to "the character ' and the range from ' to '", which is syntactically valid in regex but functionally equivalent to ['].

In the context of the annotated C# class property on the MSDN:

[RegularExpression(@"^[A-Z]+[a-zA-Z''-'\s]*$")]
public string Genre { get; set; }

it's very likely simply a mistake by he tutorial author. The original intention is hard to guess. The following exactly the same thing.

[RegularExpression(@"^[A-Z]+[a-zA-Z'\s]*$")]
public string Genre { get; set; }

answered Jan 06 '18 at 08:36

Tomalak

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Does this answer add anything new compared to the answer on the dup from 2012? – Nisse Engström Jan 06 '18 at 08:51
No, it doesn't. (Except that there's less speculation about other languages than C#). Posted the answer before I saw the duplicate comment. – Tomalak Jan 06 '18 at 08:55
I'm asking because it seems odd that you would hammer it open and then post a virtually identical answer, but I guess you missed that it was closed as a dup of **two** questions. – Nisse Engström Jan 06 '18 at 10:02
Yeah, it was a bit of a mix-up. I re-opened it because ot the first (the generic "what does this regex mean?") and got to work on the answer before I noticed the other one. – Tomalak Jan 06 '18 at 15:19

What does ''-' mean in ^[A-Z]+[a-zA-Z''-'\s]*$?

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