//echo -a $regex(guest12343,/([0-9]){5}/) $regml(1)
In this case $regex returns 1 and $regml(1) the last match number (3)

//echo -a $regex(guest12343,/([0-9]){4,5}/) $regml(1)
1st question:
Why $regex returns 0 in the last example? it´s look like the 1st case only I change 5 times for 4 or 5 times.

2nd question: How I Can return the whole number and not only the last number match? (with $regml)

As usual, when you're trying to pass a comma as a character in an identifier it needs to be escaped:



Or assign the expression to a local variable:



In this case though, you can just change the expression slightly to erradicate the need for a {} quantifier:



Which also answers your second question, enclosing the whole part that matches the full number in parentheses i.e. ([0-9]{4,5}) instead of ([0-9]){4,5} will make it capture the whole number rather than the first one matched

Both questions can be answered with the same answer
Put the {4,5} inside the ().



Just in case you were wondering, \d is the same as [0-9].

For some reason {N,N} doesn't need to be escaped.

Not in all cases, just whenever the comma is enclosed in parentheses, (\d{4,5}) not (\d){4,5}, works this way with all identifiers. Check out $remove(a(,b,)c,(,b,))

Oh, never knew about that, handy little feature. Thanks.

Thanks for the good explanation