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How do I find the array element directly preceeding a 'match'?

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Contributed by Anonymous Monk on Oct 13, 2000 at 00:08 UTC
Q&A  > arrays


I am using a "foreach" to loop over every element, and call last as soon as I find a match. This is stored in a variable and I would like to store the preceeding list element in a seperate variable. Any tips?

Answer: How do I find the array element directly preceeding a 'match'?
contributed by amelinda

Try this:

foreach $item (@array) { if (matches($item)) { $found = $last; last; } $last = $item; }
where $last holds the "preceeding list element" of the current item and $found holds the "preceeding list element" of the item that matches.

Answer: How do I find the array element directly preceeding a 'match'?
contributed by ton

Or you could just use a for loop, and eliminate the need for multiple assignments:

for ($i=0; $i<scalar(@array); ++$i) { last if (matches($array[$i])); } $found = $array[$i-1] if ($i);

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