PS: I think you can remove the last .*, leaving the assertion like this:
(?=.*8), and it will still work fine and probably faster (which dosen't
matter under these conditions). But I haven't tried that one (and have
already erased the test file I did to check the regular expression).
2007/2/9, Martin Alterisio <malterisio777@xxxxxxxxx>:
If you want to do it in one regular expression, without listing each case,
you can use a lookahead assertion:
/^(?=.*8.*)[0-9]{4}$/
The assertion (?=.*8.*) checks that the following matches the expression
contained (.*8.*) which fails if there is not an 8.
2007/2/9, Peter Lauri <lists@xxxxxxxxxxx>:
>
> Best group member,
>
>
>
> I want to match a four digit number. I allow user to enter with *
> syntax. So
> 8* would match anything that starts with 8 and is 4 digit long so:
>
>
>
> /^8[0-9]{3}$/
>
>
>
> That was easy. Ok then my other case was: *8, so anything that ends with
> 8
>
>
>
> /^[0-9]{3}8$/
>
>
>
> Ok, now the tricky one comes: *8*, so match it incase 8 is anywhere in
> the
> number. Can be beginning, end or in the middle. The problem that I face
> I
> cannot find out a good way of doing this correctly. So I ended up with
> an
> expression like this:
>
>
>
> /^(8[0-9]{3}|[0-9]8[0-9]{2}|[0-9]{2}8[0-9]|[0-9]{3}8)$/
>
>
>
> This takes care of it and everything, BUT it is so ugly. What I actually
>
> need to construct is: A regular expression that checks if 8 is a part of
> the
> number, and then that it is four digit long.
>
>
>
> The pipe "|" is an OR operator, but are there not any "AND" operator in
> Regular Expressions? I have been trying to figure this out for a while
> now.
> Of course I am using the above syntax right now, but would like to strip
> it
> down. Maybe not for the performance, but for the beauty of it :-)
>
>
>
> If you have any comments and suggestions about this I would be happy.
>
>
>
> Best regards,
>
> Peter Lauri
>
>
>
> <http://www.dwsasia.com/> www.dwsasia.com - company web site
>
> <http://www.lauri.se/> www.lauri.se - personal web site
>
> < http://www.carbonfree.org.uk/> www.carbonfree.org.uk - become Carbon
> Free
>
>
>
>
