use strict; use warnings;

use Data::Dumper; # nice

my @Data; # bad name, what does it store?

while(<DATA>){
    my($meth,$list,$count)= split ',';

    push @Data, { 'meth'=>$meth, 'list'=>$list, 'count'=>$count };

}
print "Unsorted:\n", Dumper( @Data ), "\n";

@Data = sort { $a->{'meth'} cmp $b->{'meth'} } @Data;
# swap $a and $b if you want the other direction

print "Sorted:\n", Dumper( @Data ), "\n";


__DATA__
def,phyton\tjavascript,2
abc,perl\terlang\tlisp,1
ghi,arc\truby\tprolog,3
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also, avoid using $a and $b when not sorting. They will confuse you, because they are global. Not a problem in your code here though.
hth

Update: You had another question which I overlooked:
the value you get, 2HASH(0x225e44), tells you that you have not a value, but a hash, which will have to be dereferenced to get at whatever is in the hash, for example using the keys function:

my %dd;
$dd{'1'}{'2'}{'3'}="hi";
$dd{'1'}{'3'}{'5'}="hello";
print "\nkeys in hash: ", join ' ', keys %{ $dd{'1'} };
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