Regular expression to match a #

Duncan Booth duncan.booth at invalid.invalid
Fri Aug 12 09:49:24 CEST 2005


John Machin wrote:

>> Your wording makes it hard to distinguish what exactly is "dopey".
>> 
> 
> """
> dopey implementations of search() (which apply match() at offsets 0, 1, 
> 2, .....).
> """
> 
> The "dopiness" is that the ^ operator means that the pattern cannot 
> possibly match starting at 1, 2, 3, etc but a non-optimised search will 
> not recognise that and will try all possibilities, so the failing case 
> takes time dependant on the length of the string.

The ^ operator can match at any position in the string if the preceding 
character was a newline. 'Dopey' would be failing to take this into 
account.



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