Finding / Replacing repetetive characters from a string in a Regular expression.

nims has asked for the wisdom of the Perl Monks concerning the following question:

Hi all, I am searching for a way to find repetetive characters from a string and work with them. I have found something that works, but looking at it, it doesn't look like the right solution to me. I was hoping some of you know a better solution. Here's my code:

    my @numbers = $aKnosID =~ m/([a]{2,}|[b]{2,}|[c]{2,}|[d]{2,}|[e]{2
+,}|[f]{2,}|[g]{2,}|[h]{2,}|[i]{2,}|[j]{2,}|[k]{2,}|[l]{2,}|[m]{2,}|[n
+]{2,}|[o]{2,}|[p]{2,}|[q]{2,}|[r]{2,}|[s]{2,}|[t]{2,}|[u]{2,}|[v]{2,}
+|[w]{2,}|[x]{2,}|[y]{2,}|[z]{2,})/g;
    if ( @numbers > 0 ) {
        #repetetive strings here;
        for ($i=0;$i<@numbers;$i++) {
            #Do something
        }
    }
    else {
    }
[download]

Comment on Finding / Replacing repetetive characters from a string in a Regular expression. Download Code

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Re: Finding / Replacing repetetive characters from a string in a Regular expression. by deibyz (Hermit) on Oct 14, 2004 at 13:33 UTC
I'm not very sure what you're trying to do, but a simple `m\|([a-z])(\1)+\|;` should be enough to catch repetitive characters.	[reply] [d/l]
Re^2: Finding / Replacing repetetive characters from a string in a Regular expression. by nims (Novice) on Oct 14, 2004 at 14:27 UTC
Sorry, that doesn't work. The solution that really works is above: `grep {length > 1} $aKnosID =~ /(([a-z])\2+)/g;`	[reply] [d/l]
Re: Finding / Replacing repetetive characters from a string in a Regular expression. by JediWizard (Deacon) on Oct 14, 2004 at 13:29 UTC
It looks to me like your expression is the equivilent of : `my @numbers = $aKnosId =~ m/([a-z]{2,})/g` Update I was totally wrong... sorry. Try this: `my @numbers = $aKnosId =~ m/(([a-z])(?:(?=\2)[a-z])+)/g` But then again Roy's answer is better. May the Force be with you	[reply] [d/l] [select]
Re^2: Finding / Replacing repetetive characters from a string in a Regular expression. by Roy Johnson (Monsignor) on Oct 14, 2004 at 13:33 UTC
The difference is that your expression will match two (or more) different characters, while the OP wants to match two (or more) of the same. This should do it. `my @numbers = $aKnosId =~ /(([a-z])\2+)/g;` [download] Except that both captures get returned. So to fix: `my @numbers = grep {length > 1} $aKnosId =~ /(([a-z])\2+)/g;` [download] Caution: Contents may have been coded under pressure.	[reply] [d/l] [select]
Re^3: Finding / Replacing repetetive characters from a string in a Regular expression. by nims (Novice) on Oct 14, 2004 at 14:28 UTC
Thank you! Your solution works great :D.	[reply]