note
hippo
<p>If I understand you correctly (and maybe not, see [id://1154672]) you want this:</p>
<ol>
<li>Find the position of the first 'x'.</li>
<li>Find the position of the second 'x'.</li>
<li>Take the difference in these positions, add it to the second position and look here for the third 'x'.</li>
<li>If all that succeeds you have a match.</li>
</ol>
<p>In which case, just code this up with a loop and judicious use of [doc://index] and [doc://substr].</p>
<p>However, this does sound rather like an [XY Problem]. Perhaps if you explained why you want to do this in the first place a much better solution might become apparent.</p>
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