lanx@ubuntu:~$ perl -MTime::HiRes=time -e'my @a= 0..1e6;my $t= time;my @bla=@a; tr/h//d for @bla;print time-$t; <>'
2.48298692703247
lanx@ubuntu:~$ perl -MTime::HiRes=time -e'my @a= 0..1e6;my $t= time;my @bla= map{tr/h//d; $_} @{\@a};print time-$t; <>'
7.50910615921021
lanx@ubuntu:~$ perl -MTime::HiRes=time -e'my @a= 0..1e6;my $t= time;my @bla= map{tr/h//d; $_}map{$_} @a;print time-$t; <>'
8.25657296180725