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

[jynx]

in reply to Re: Unique array w/o repeated elements and still keep the original order!
in thread Unique array w/o repeated elements and still keep the original order!

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 :-)

[DamnDirtyApe]

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

Exactly the point. In your code, each iteration of the loop assigns the next row to $_ (your while statement), then assigns the following line to $line_holder. The line assigned to $_ is never handled, so it just get's "skipped."

In any case, couldn't the whole process be reduced to

my %seen = () ;
my @uniq_rows = grep { !$seen{$_}++ } <FILE> ;

?


_______________
DamnDirtyApe

Those who know that they are profound strive for clarity. Those who
would like to seem profound to the crowd strive for obscurity.
            --Friedrich Nietzsche

[demerphq]

Er just a thought but any time ive written that code ive ended up changing it to

my @unique=map{chomp; $_{$_}++ ? () : $_} <FILE>;

or something like it (i dont always use %_ but sometimes i do, blame ABIGAIL-II ;-)

To be honest i think that in my perl career ive only used a grep a few times. map seems to be so much more useful in that it can do grep()s job, and more as well!

Yves / DeMerphq
---
Software Engineering is Programming when you can't. -- E. W. Dijkstra (RIP)