$#a is the last index of the array @a. setting it to something lower than what it already is will truncate the array. 
@a = (0..10);
print join(" ", @a), "\n";
$#a = 5;
print join(" ", @a), "\n";

[download]
0 1 2 3 4 5 6 7 8 9 10
0 1 2 3 4 5

In reply to Re: I've never seen this before - $#a = 4 - ?? by robobunny
in thread I've never seen this before - $#a = 4 - ?? by emilford

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