my @array = (
     {x => 1,
      y => 2,
      z => 3},
     {x => 4,
      y => 5,
      z => 6},
   #etc
);

##</code><code>##

grep {$_->{x} == 4 } @array;

##</code><code>##

my @newarray = grep {$_->{x} == 4 } @array;