Re: Match First Sequence in Regular Expression?

"Jordan Abel" <random832@xxxxxxxxx> wrote in message
news:slrndthvsh.2npi.random832@xxxxxxxxxxxxxxxx
> On 2006-01-26, Roger L. Cauvin <roger@xxxxxxxxxxxx> wrote:
>> Say I have some string that begins with an arbitrary sequence of
>> characters
>> and then alternates repeating the letters 'a' and 'b' any number of
>> times,
>> e.g.
>>
>> "xyz123aaabbaabbbbababbbbaaabb"
>>
>> I'm looking for a regular expression that matches the first, and only the
>> first, sequence of the letter 'a', and only if the length of the sequence
>> is
>> exactly 3.
>>
>> Does such a regular expression exist? If so, any ideas as to what it
>> could
>> be?
>
> I believe posix regex libraries always yield only the first match.
>
> by "exactly 3" do you mean "Four shalt thou not count, neither count
> thou two, excepting that thou then proceed to three. Five is right
> out.", or do you mean the first occurence of 3 a's no matter what
> follows it?

Someone on another newsgroup provided a solution:

..*?(?<![ab])aaab

--
Roger L. Cauvin
nospam_roger@xxxxxxxxxx (omit the "nospam_" part)
Cauvin, Inc.
Product Management / Market Research
http://www.cauvin-inc.com


.

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