perl?

[semna]

Hi
I am writing a script in perl. My question is about of part of this script. I have a subroutine that makes a problem. Everything is OK when I don't use SUB but when I use it just give me the first part of the file (just $i=0). but it seems should work as a loop. Any command appreciated.
sub edit
{
my ($list) = @_;
my @species = "";
my $pid = "";
my @tree = "";
@species = split "//", $list;
while(my $i = 0; $i < scalar @species; $i++) {
if($species[$i] =~ /RANK *: subspecies/ && $species[$i] =~ /PARENT ID * : (\d+)/){
$pid = $1;
# # print "$pid\n";
$species[$i] = `getz "[taxonomy:$pid]" -e`;
@tree = $species[$i];
return @tree;
}
}
}

[semna]

moreover, curly braces are OK.

[kmcarr]

Semma,

You exit the subroutine with the "return @tree;". As soon as it reaches that point during the first pass ($i=0) program flow returns to the calling point without processing the remainder of your @species list.

[semna]

Hi KmCarr,
I am a new user in perl. As I learn, return is needed for subroutine. So where should I do?
Thanks

[krobison]

In general, you don't want to return from withing

Also, when posting code here go to Advanced and use the CODE tags (# icon), as this makes examples much easier to read

sub edit
{
  my ($list) = @_;
  my @species = "";
  my $pid = "";
  my @tree = "";
  @species = split "//", $list;
  while(my $i = 0; $i < scalar @species; $i++) 
  {
    if($species[$i] =~ /RANK *: subspecies/ && $species[$i] =~ /PARENT ID * :    (\d+)/)
    {
       $pid = $1;
       # # print "$pid\n";
       $species[$i] = `getz "[taxonomy:$pid]" -e`;
       @tree = $species[$i];
       return @tree;
    }
  }
}

What you do depends on what you want. One solution is to return a much more sophisticated data structure which has all of the results in it (for example, a hash keyed by species with a reference to the tree list in the value)

Alternatively, do the split outside the subroutine and run the subroutine once on each value (I'm guilty of also editing your code to my style to be more concise). Also, you are always better using a foreach loop than explicit iteration (harder to make errors, more efficient, clearer in intent)

  my @species = split "//", $list;
foreach my $species(@species);
  {
    my @tree=&edit($species);
    ## do something here
}

sub edit
{
     my ($species) = @_;
    if($species =~ /RANK *: subspecies/ && $species =~ /PARENT ID * :    (\d+)/)
    {
       my $pid = $1;
       # # print "$pid\n";
       return `getz "[taxonomy:$pid]" -e`;
    }
}

[semna]

Thanks So much Krobison for your help.