Even though I don't understand what "for my $i (0 .. $#arr)"

$#array is the index of the last element of @array. Which is the same as the scalar(@array)-1;

a subroutine can change variables from the function it was called from

Yes, if you modify @_, it changes for the caller.

In reply to Re^3: Array value changing for some reason by kschwab
in thread Array value changing for some reason by Silt

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