The map function lets you apply some code to each element of a list. Usually, your code won't have any side effects; indeed, the documentation does not guarantee a particular evaluation order. In practice, elements are evaluated in order, so we can write this code to keep a running count of the values in @a.
my $sum;
@sums = map {$a += $_} @a;

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In reply to computing a running total with with map by ariels

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