CODEWITHSUNDEEP
perlloopswhile-loop
user1701252
user1701252

Reputation: 1581

Perl while loop is repeating itself

I am 100% new to Perl but do have some PHP knowledge. I'm trying to create a quick script that will take the @url vars and save it to a .txt file. The problem that I'm having is that it's saving the url again everytime it runs through the loop which is super annoying. So when the loop runs, it'll look like this. 

url1.com
url1.com url2.com
url1.com url2.com url3.com

What I would like it to look like is just a plain and simple:

url1.com
url2.com
url3.com

Here is my code. If anyone can help, I would appreciate it SO SO much!

#!/usr/bin/perl
use strict;
use warnings;

my $file = "data.rdf.u8";
my @urls;

open(my $fh, "<", $file) or die "Unable to open $file\n";

while (my $line = <$fh>) {

    if ($line =~ m/<(?:ExternalPage about|link r:resource)="([^\"]+)"\/?>/) {
        push @urls, $1;
    }

    open (FH, ">>my_urls.txt") or die "$!";
    print FH "@urls ";
    close(FH);
}

close $fh;

Upvotes: 3

Views: 234

Answers (3)

raina77ow
raina77ow

Reputation: 106483

Shouldn't this part:

open (FH, ">>my_urls.txt") or die "$!";
print FH "@urls ";
close(FH);

...be placed outside of while loop? It makes no sense within while, as @urls are apparently incomplete there.

And two regex-related sidenotes: first, with m operator you may choose another set of delimiters so you don't have to escape / sign; second, it's not necessary to escape " sign within character class definition. In fact, it's not required to escape it in regex at all - unless you choose this character as a delimiter. )

So your regex may look like this:

$line =~ m#<(?:ExternalPage about|link r:resource)="([^"]+)"/?>#

Upvotes: 4

Tudor Constantin
Tudor Constantin

Reputation: 26871

do you need the @urls array elsewhere? because else, you could simply:

#!/usr/bin/perl
use strict;
use warnings;

my $file = "data.rdf.u8";
my @urls;

open(my $fh, "<", $file) or die "Unable to open $file\n";
open (FH, ">>my_urls.txt") or die "$!";
while (my $line = <$fh>) {
    if ($line =~ m/<(?:ExternalPage about|link r:resource)="([^\"]+)"\/?>/) {

      print FH $1;

    }



}
close(FH);
close $fh;

Upvotes: 2

AntonPiatek
AntonPiatek

Reputation: 823

Your print is inside your while loop. It sounds like you want to move your print outside of the loop.

Or if you want to print each url as you go through each line, move the declaration of "my @urls" down into the loop, then it will get reset each line

Upvotes: 8

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