A simple optimization would be to replace 

for (0..($strLen-1))

[download]
with 
for ( 0..$strLen/2 )

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One could get fancier by testing only those cycle lengths that are either 1 or prime factors of $strLen, which could make a difference for long strings.

Also, I think it's simpler just to test for equality of $str and $copy, obviating the xor and the regex: 

for ( 1..$strLen/2 )
  {
  $copy .= substr $copy, 0, 1, '';
  return wantarray  ? ($_, substr $str, 0, $_) : $_
    if $copy eq $str;
  }

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the lowliest monk

In reply to Re: Find repeated patterns in strings by tlm
in thread Find repeated patterns in strings by GrandFather

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