From: Ammar Ali <ammarabuali@...>
Date: 2010-11-03T06:54:00+09:00
Subject: Re: Regular Expression

On Tue, Nov 2, 2010 at 11:34 PM, Richard Conroy
<richard.conroy@gmail.com> wrote:
> On Tue, Nov 2, 2010 at 9:05 PM, Dv Dasari <dv.mymail@gmail.com> wrote:
>
>> I am trying to write a reqular expression to match a word with my input
>> string.
>>
>> Input string can be ( inpstr = ABCDD )
>>
>> Any suggestion on how I can fix this?

Take a look at looakahead and lookbehind assertions. They used to
conditionally match when followed or preceded by a given pattern.

> OTOH this regex might scratch your itch:
> /^A?B?C?D{0,2}$/

Note that the last quantifier here (the {0,2}) only applies to the
last character, the D, not the whole expression.

>> "ABBC" =~ /^A?B?C?D{0,2}$/
=> nil

HTH,
Ammar