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Re: Finding repeat sequences.

by choroba (Cardinal)
on Jun 18, 2013 at 19:10 UTC ( [id://1039633]=note: print w/replies, xml ) Need Help??


in reply to Finding repeat sequences.

"abcdabcdabceabcdabcdabceab" =~ /(.+).*\1/
returns
abcdabcdabce

Can you give more input samples to exemplify the other constraints?

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

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Re^2: Finding repeat sequences.
by BrowserUk (Patriarch) on Jun 18, 2013 at 19:59 UTC

    They are kind of hard to come up with, but okay.

    Given the rep 'aaaabaaaaba' and a string containing one whole and one partial rep 'aaaabaaaabaaaaabaaaab'

    $s = 'aaaabaaaabaaaaabaaaab';; $s =~ m[(.+).*\1] and print $1;; aaaabaaaab

    Which isn't correct because:

    aaaabaaaabaaaaabaaaab aaaabaaaab aaaabaaaab 1 ^2

    You can fix that by removing the redundant .* per LanX's version: m[(.+)\1] but then you get:

    $s = 'aaaabaaaabaaaaabaaaab';; $s =~ m[(.+)\1] and print $1;; aaaab

    Which isn't right:

    aaaabaaaabaaaaabaaaab aaaabaaaab aaaabaaaab 1 2 ^3 4

    I realise that this is a 'cheat' as there in no complete repetition to find, but it is one possible scenario.

    Given the string will always consist of 1 or more repetitions of the substring, whatever partial substring (if any) is at the end of the string should match the same number of characters at the start of the string. That's the bit I'm having trouble wrapping my head around.


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