While considering a previous perl question, I was reminded of an odd occurance for a bit of code. The line  $idx{$val} ||= 1 && push @num, $val; in the below snippet will store the selection count of $val into $idx{$val} rather than the value 1 as expected. For example, if the number in $val is the fourth number selected from the random sequence , this code will store the value 4 in $idx{$val}. I'm at a loss as to why this would happen. Interestingly, if the same value occurs in the random sequence a second time (ie the $idx{$val} is already defined), the code will not change the count in $idx{val}. Any ideas? 
my %idx = ();
my $val = 0;
my @num = ();
my $nrndded = 3;
my $ulmt = 10;
while(scalar keys %idx < $nrneeded){
    $val = int(rand($ulmt-1)+1);   # map range to (1..ulmt)
    $idx{$val} ||= 1 && push @num, $val;
}

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In reply to Short Circuit Operator and Hash Assignment by periapt

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