my %hash; # hash of hashes already defined and filled in an earlier part of code

foreach (sort keys %{$hash{$key1}}){
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+AAA/gi){
    print "found1\n";
    }
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+BBB/gi){
    print "found2\n";
    }
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+CCC/gi){
    print "found3\n";
    }
}

##</code><code>##

 found2
 found3
 found2
 found3
 ...

##</code><code>##

foreach (sort keys %{$hash{$key1}}){
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+AAA/gi){
    print "found1\n";
    }
# copied from above and changed the output to 'foundx'
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+AAA/gi){
    print "foundx\n";
    }
#
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+BBB/gi){
    print "found2\n";
    }
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+CCC/gi){
    print "found3\n";
    }
}

##</code><code>##

 foundx
 found2
 found3
 foundx
 found2
 found3
 ...