Difference Between The 2 Statements

  • Thread starter Thread starter RN1
  • Start date Start date
R

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,

Ron
 
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,
Click to expand...


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.
 
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