preg_match_all仅返回第一个匹配项

Question

Ok so basically I'm trying to walk through a large amount of html code that contains hyperlinks towards files. I'm using preg_match_all to find all occurrences. However, it's never returning the amount of matches expected.

Shot HTML code (value of $content):

<a class="file_download file_ext_docx" href="/download.php?f=/LiO2beoordeling%20door%20mentor%20Maartje%20ingevuld.docx">Download file 1.docx</a><br /><em>Some text<a class="file_download file_ext_docx" href="/download.php?f=/BP3/Referenties.docx">Download file 2.docx</a> </strong><br /><strong>- Some text: <a class="file_download file_ext_docx" href="/download.php?f=/Zelfevaluatie%204.2.docx">Download file 3.docx</a> Soem text: <a class="file_download file_ext_docx" href="/download.php?f=/BP3/sz-lio.docx">Download file 4</a> </strong><br /><a class="file_download file_ext_docx" href="/download.php?f=/BP3/poplio.docx">

PHP code:

preg_match_all('/download\.php\?f=(.*?)">/', $content, $matches);
foreach($matches as $val){
    echo $val[0] ."<br />";
}

The code above only returns the first match for me. Strangely enough, echoing:

echo $val[1] ."<br />"; //Returns 2nd match
echo $val[2] ."<br />"; //Returns 3rd match
//etc

So I figured I should just count the array and wrap it around in a for loop to solve this problem. However:

count($matches); //Returns 1

Answer 1

First, you should read carefuly the php.net documentation http://php.net/manual/en/function.preg-match-all.php

But in resume, preg_match_all put in $matches the results depending the flag you use: PREG_PATTERN_ORDER by default so the $matches array should be

Orders results so that $matches[0] is an array of full pattern matches, $matches[1] is an array of strings matched by the first parenthesized subpattern, and so on.

in your case:

Array
(
    [0] => Array
        (
            [0] => download.php?f=/LiO2beoordeling%20door%20mentor%20Maartje%20ingevuld.docx">
            [1] => download.php?f=/BP3/Referenties.docx">
            [2] => download.php?f=/Zelfevaluatie%204.2.docx">
            [3] => download.php?f=/BP3/sz-lio.docx">
            [4] => download.php?f=/BP3/poplio.docx">
        )

    [1] => Array
        (
            [0] => /LiO2beoordeling%20door%20mentor%20Maartje%20ingevuld.docx
            [1] => /BP3/Referenties.docx
            [2] => /Zelfevaluatie%204.2.docx
            [3] => /BP3/sz-lio.docx
            [4] => /BP3/poplio.docx
        )

)

So if you want to list all the results, you can just do

foreach($matches[0] as $val){
    echo $val ."<br />";
}

Answer 2

Your pattern is right, but you look in the wrong place
when i dump your result i found it ok:

array(2) {
  [0]=>
  array(5) {
    [0]=>
    string(75) "download.php?f=/LiO2beoordeling%20door%20mentor%20Maartje%20ingevuld.docx">"
    [1]=>
    string(38) "download.php?f=/BP3/Referenties.docx">"
    [2]=>
    string(42) "download.php?f=/Zelfevaluatie%204.2.docx">"
    [3]=>
    string(33) "download.php?f=/BP3/sz-lio.docx">"
    [4]=>
    string(33) "download.php?f=/BP3/poplio.docx">"
  }
  [1]=>
  array(5) {
    [0]=>
    string(58) "/LiO2beoordeling%20door%20mentor%20Maartje%20ingevuld.docx"
    [1]=>
    string(21) "/BP3/Referenties.docx"
    [2]=>
    string(25) "/Zelfevaluatie%204.2.docx"
    [3]=>
    string(16) "/BP3/sz-lio.docx"
    [4]=>
    string(16) "/BP3/poplio.docx"
  }
}