Welcome to the Monastery, kdarbs!

What have you tried? See How (Not) To Ask A Question.

It seems you could naively use substr, perhaps like this (untested):

# rename %hash to %str2pos, as that seems an accurate name
my %str2pos = ( anee => '1', jane => '0', neen => '2', );
my $result;
for my $string(keys %str2pos) {
    substr($result,$str2pos{$string},length($string),$string);
}
print "$result\n";
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