Difference Between The 2 Statements

Difference Between The 2 Statements

am 13.04.2008 13:39:07 von rn5a

Consider the following RegularExpression:

====================
q[^u]
====================

One of the RegEx tutorials I have come across says the following
w.r.t. the above RegEx:

====================
The above RegEx does not mean a 'q' not followed by a 'u'; rather it
means a 'q' followed by a character that is not a 'u'.
====================

Now what's the difference between the 2 statements that I have cited
above?

Thanks,

Ron

Re: Difference Between The 2 Statements

am 13.04.2008 14:49:34 von Jesse Houwing

Hello RN1,

> Consider the following RegularExpression:
>
> ====================
> q[^u]
> ====================
> One of the RegEx tutorials I have come across says the following
> w.r.t. the above RegEx:
>
> ====================
> The above RegEx does not mean a 'q' not followed by a 'u'; rather it
> means a 'q' followed by a character that is not a 'u'.
> ====================
> Now what's the difference between the 2 statements that I have cited
> above?
>
> Thanks,


condider this input:

q

this could be read as a q not followed by a u.

condider

qd

this could be read as a q not followed by a u.

in regex this would be written as:

q(?!u)

The other regex however will never match the first option, because q[^u]
alsways needs to match at least 2 characters, a q and a different character
than u.


--
Jesse Houwing
jesse.houwing at sogeti.nl

Re: Difference Between The 2 Statements

am 13.04.2008 19:17:52 von Peter Morris

q followed by anything as long as it is not q == match
q followed by q == no match

Re: Difference Between The 2 Statements

am 14.04.2008 13:33:35 von nomailreplies

Also, q followed by nothing = no match



Juan T. Llibre, asp.net MVP
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======================================
"Peter Morris" wrote in message news:uR7P20gnIHA.5820@TK2MSFTNGP04.phx.gbl...
>q followed by anything as long as it is not q == match
> q followed by q == no match