foreach loop with nested

cdherold has asked for the wisdom of the Perl Monks concerning the following question:

monks,

Using a foreach loop works fine, but when I try to put in a nested "if" statement the program doesn't seem to work.

I'm trying to screen throught the contents of a webpage to determine if a company is listed. If it is listed, I want to pull out the information starting at the company name ($company) until the tag </tr>.

I need to determine if the company is listed before doing the extraction.

The basic code without determining if the company is listed or not before extracting works fine.

This works ...

$content = get($url);

@companies = ("AOL Time Warner", "Genetech","Broadwing");

foreach $company (@companies){

             $content =~ /$company(.*?)<\/tr>/gsmi;

             $new_coverage = $1;

             print "$new_coverage <p>"

}
[download]

BUT when I try to put the if statement within the foreach loop, it doesn't seem to work.

This doesn't work ...

$content = get($url);

@companies = ("AOL Time Warner", "Genetech","Broadwing");

foreach $company (@companies){

  if  ($content =~ /$company/gsmi){

             $content =~ /$company(.*?)<\/tr>/gsmi;

             $new_coverage = $1;

             print "$new_coverage <p>";
}

}
[download]

Any idea's on why this is happening?

thanks

Comment on foreach loop with nested Select or Download Code

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Re: foreach loop with nested by John M. Dlugosz (Monsignor) on Aug 02, 2001 at 02:23 UTC
I think the /g modifier is messing you up. You never finish the iteration, so the next match against the same string will find the next match, which fails if there is only one. So the if line you added "eats" the match and then the next line sees no more matches available. try `if ($content =~ /$company(.*?)<\/tr>/smi) { $new coverage= $1; #etc }` [download]	[reply] [d/l]
Re: Re: foreach loop with nested by cdherold (Monk) on Aug 02, 2001 at 08:09 UTC
john, that /g modifier was the problem ... thanks very much. chris	[reply]
Re: foreach loop with nested by japhy (Canon) on Aug 02, 2001 at 01:37 UTC
Why are you using the `/gmsi` modifiers? Do you know what any of them do? I can't be sure from your code, but I think you can remove the `/g` and the `/m` safely. _____________________________________________________ Jeff `japhy` Pinyan: Perl, regex, and perl hacker. `s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;`	[reply]
Re: foreach loop with nested by arturo (Vicar) on Aug 02, 2001 at 02:41 UTC
In general, the construction `$content =~ /foo(.?)bar/; $new_coverage = $1;` [download] Is cumbersome and error-prone -- if that match doesn't occur, $1 won't contain what you expect it to contain. So do it in one step -- capture the match into a variable, and see if it's defined (this version will grab each match and display it): `while (my ($new_coverage) = ($content =~ /$company(.?)<\/tr>/ig ) ) { print "$new_coverage\n"; }` [download] update wrote that a little quickly. runrig pointed out, quite correctly, that this regex will produce an infinite loop. What will work is `if (my @new_coverage = ($content =~ /$company(.?)<\/tr>/isg) ) { print "$_\n" foreach @new_coverage; }` [download] props, of course, to runrig </update>* I'm guessing that you're snagging a web page with news about these companies, and that there may be more than one content item per company (otherwise the /g modifier and the while loop don't make sense). If this is what you're doing, there might be a need to add the /s to that regex as well (because you may want . to match a newline). `perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); +$rose = "smells sweet to degree $n"; other_name = rose; print "$oth +er_name\n"'` [download]	[reply] [d/l] [select]
Re: foreach loop with nested by runrig (Abbot) on Aug 02, 2001 at 03:55 UTC
Another way (and I hope your using strict and warnings if this is part of a larger script) (: `my @companies = ("AOL Time Warner", "Genetech","Broadwing"); my $companies = join('\|',map(quotemeta, @companies)); $companies = qr/($companies)(.*?)/is; while ($content =~ /$companies/g) { print "Company: $1 new coverage: $2\n"; }` [download]	[reply] [d/l]