PHP：正则表达式在文件中搜索模式并选择它

Question

I am really confused with regular expressions for PHP.

Anyway, I cant read the whole tutorial thing now because I have a bunch of files in html which I have to find links in there ASAP. I came up with the idea to automate it with a php code which it is the language I know.

so I think I can user this script :

$address = "file.txt"; 
$input = @file_get_contents($address) or die("Could not access file: $address");
$regexp = "??????????"; 
if(preg_match_all("/$regexp/siU", $input, $matches)) { 
    // $matches[2] = array of link addresses 
   // $matches[3] = array of link text - including HTML code 
} 

My problem is with $regexp

My required pattern is like this:

href="/content/r807215r37l86637/fulltext.pdf" title="Download PDF

I want to search and get the /content/r807215r37l86637/fulltext.pdf from above lines which I have many of them in the files.

any help?

==================

edit

title attributes are important for me and all of them which I want, are titled

title="Download PDF"

Answer 1

Once again regexp are bad for parsing html .

Save your sanity and use the built in DOM libraries.

$dom = new DOMDocument();
@$dom->loadHTML($html);
$x = new DOMXPath($dom);
    $data = array();
foreach($x->query("//a[@title='Download PDF']") as $node)
{
    $data[] = $node->getAttribute("href");
}

Updated code based on ircmaxell comment.

Answer 2

try something like this. If it does not work, show some examples of links you want to parse.

<?php
$address = "file.txt"; 
$input = @file_get_contents($address) or die("Could not access file: $address");
$regexp = '#<a[^>]*href="([^"]*)"[^>]*title="Download PDF"#'; 

if(preg_match_all($regexp, $input, $matches, PREG_SET_ORDER)) { 
  foreach ($matches as $match) {
    printf("Url: %s<br/>", $match[1]);
  }
} 

edit: updated so it searches for Download "PDF entries" only

Answer 3

That's easier with phpQuery or QueryPath :

foreach (qp($html)->find("a") as $a) { 
    if ($a->attr("title") == "PDF") {
        print $a->attr("href");
        print $a->innerHTML();
    }
}

With regexps it depends on some consistency of the source:

preg_match_all('#<a[^>]+href="([^>"]+)"[^>]+title="Download PDF"[^>]*>(.*?)</a>#sim', $input, $m);

Looking for a fixed title="..." attribute is doable, but more difficult as it depends on the position before the closing bracket.

Answer 4

The best way is to use DomXPath to do the search in one step:

$dom = new DomDocument();
$dom->loadHTML($html);
$xpath = new DomXPath($dom);

$links = array();
foreach($xpath->query('//a[contains(@title, "Download PDF")]') as $node) {
    $links[] = $node->getAttribute("href");
}

Or even:

$links = array();
$query = '//a[contains(@title, "Download PDF")]/@href';
foreach($xpath->evaluate($query) as $attr) {
    $links[] = $attr->value;
}

Answer 5

href="([^]+)"将为您提供该表格的所有链接。