Re^2: REgular expression to check the string that allows "a","b" and "c" to occur only once in any order.

This looks like overkill.

If a string is required to contain all of an "a", a "b" and a "c" and its length is limited to 3, then it can only contain one of each.

So this ought to suffice:

/^(?=.*a)(?=.*b)(?=.*c).{3}\z/
[download]

Of course, yours is the way to go if the length is not limited to 3.

Comment on Re^2: REgular expression to check the string that allows "a","b" and "c" to occur only once in any order. Download Code

Replies are listed 'Best First'.
Re^3: REgular expression to check the string that allows "a","b" and "c" to occur only once in any order. by BrowserUk (Patriarch) on Dec 11, 2007 at 14:55 UTC
Agreed, for the simple case, but it trivially extends to any number of unqiue characters within strings of a specified length. (Think crossword, hangman etc. :) Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply]

Replies are listed 'Best First'.

Re^3: REgular expression to check the string that allows "a","b" and "c" to occur only once in any order.
by BrowserUk (Patriarch) on Dec 11, 2007 at 14:55 UTC

Agreed, for the simple case, but it trivially extends to any number of unqiue characters within strings of a specified length. (Think crossword, hangman etc. :)

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

[reply]