Unique array w/o repeated elements and still keep the original order!

[chuleto1]

Please monks you are my only hope:

This piece of code opens a file an dumps contents into array. I want to get rid of possible repeated lines of text. When I run the code, it substitutes repeated elements for only one instance. Yes this is what I want but I do not want the order of the elements to change. Current implementation does not keep correct order when I dump the unique lines into a new file. Please help!

open (FILE,"$tempfile5") || die "Cannot read from $tempfile5\n";
my %hsh;

open (OUTF,">$tempfile6") || die "Cannot write to $tempfile6\n";
my @lines = <FILE>;
    
undef @hsh{@lines};
my @lines2 = keys %hsh;
    
    
foreach my $instance (@lines2)
{
   print OUTF $instance;
}

close FILE;
close OUTF;

Edited: ~Fri Aug 9 22:02:52 2002 (GMT) by footpad: Revised HTML formatting to be more appropriate, e.g. replace <I> tags with <CODE> tags and removed extraneous <BR> tags.

[tstock]

foreach my $instance (@lines2)
{
  print OUTF $instance unless $hsh{$instance}++;
}

Tiago
Update: replaced 'if' with 'unless'. thanks robobunny

[robobunny]

i'm assuming it was just a typo, but i think you meant:

foreach my $instance (@lines2)
{
  print OUTF $instance unless $hsh{$instance}++;
}

as written, it will only print the duplicates.

[TexasTess]

you don't say if the repeated lines will be in succession(one right after the other) or if they can be spread out through the file. If it's random...then this is what i'd use....

my @lines=();
open (FILE,"$tempfile5") || die "Cannot read from $tempfile5\n";
my $found = 0;
while(<FILE>){
    my $line_holder = $_; #DOH, should have had this here
    foreach my $val(@lines){
       if($val eq $line_holder){$found = 1;}
    }
    if($found){
      $found = 0; 
      next;
    }else{
       push @lines, $line_holder;
    }
}



TexasTess
"Great Spirits Often Encounter Violent Opposition From Mediocre Minds" --Albert Einstein

[jynx]

That won't work how you expect it to...

Particularly, what's happening to $_? It's getting set by the while loop and then forgotten about, which is to say that you'll not process all of the lines. Oops. How about this:

while (my $line_holder = <FILE>) {
  foreach etc...

Or alternately you could check for file EOF in the while condition like so:

while (! eof(FILE)) {
   my $line_holder = <FILE>;
   foreach etc...

Either way should fix the problem...

jynx

[TexasTess]

I'm not sure what you mean by


while (my $line_holder = <FILE>) {
  foreach etc...


That is certainly != to what I wrote....


while(<FILE>){
    my $line_holder = $_; #GOTCHA
    foreach my $val(@lines){


Which is something I do in tons of code I have written at work and it works fine?? Perhaps I am missing something?
TexasTess
"Great Spirits Often Encounter Violent Opposition From Mediocre Minds" --Albert Einstein
Waiting to see just how fast this makes it to an all time negative record...and wondering if any of the downvoters think I care :-)