#!perl
use strict;
use warnings;
use XML::Simple;
use Data::Dump 'pp';

my $blast = XMLin('BLAST1.XML');
my $hits = $blast->{BlastOutput_iterations}->{Iteration}->{Iteration_hits}->{Hit};
my $ret;
#push @ret, $_->{Hit_def} foreach (@{$hits});
foreach (@{$hits}) {
  push @{$ret},join '|', 
      $_->{Hit_def},
      $_->{Hit_num},
      $_->{Hit_hsps}->{Hsp}->{Hsp_identity};
}
pp $ret;