You have a hash with two name/value pairs.

$var1 = "2000";
$var2 = "02";
$var3 = "2000";
$var4 = "2";

$var2 does not get interpolated - ie, "02" is not the same as "2" in t
+he context you used. To force numerical context:

$array{$var2} = $array{"02"} = undefined 
$array{$var2+0} = $array{"2"} = 125
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1 and 2 are the only KEYS in the hash, so others are undefined. And I would rename %array to %hash to avoid confusion with this.

I suggest you read perldata document to familiarise yourself with Perl's data structures.

cLive ;-)

Update: - oops, misread (thanks Sifmole) - have amended above to explain.