Here is a simple yet explanatory (I hope) way of doing it:

#!/usr/bin/perl -w

use strict;
use warnings;
use diagnostics;

my @array = qw(MANGO APPLE GRAPES MANGO MANGO MANGO MANGO APPLES APPLE
+S BANANA CORN APPLES);
my %hash;
foreach (@array)
{
    $hash{$_}++;
}

for my $key(keys %hash)
{
    print "$key => $hash{$key}\n";
}
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