Perl to PHP equivalent: extract strings with regex

Question

What is the PHP equivalent for this Perl code?

my $html = '<tr class="aaa"><td class="bbb">111.111.111.111</td><td>443</td><td><div><span class="ccc"></span> example <span> example</span></div></td></tr><tr class="aaa"><td class="bbb">222.222.222.222</td><td>443</td><td><div><span class="ccc"></span> example <span> example</span></div></td></tr>';

print "$1:$2\n" while $html =~ /class="aaa"><td class="bbb">(.*?)<\/td><td>(\d+)<\/td>/g;

I tried with this code, but it gives infinite loop.

while(preg_match('/td class=\"bbb\">(.*?)<\/td><td>(\d+)<\/td>/',$html,$out)) {
        echo "$out[1]:$out[2]\n";
    }

Also, with if instead of while it gives only one result.

Expected output (IP:PORT):

111.111.111.111:443
222.222.222.222:443

Environment: Windows 7 with PHP 5.5.12 (WAMP v2.5).

Answer 1

This code will do as you ask. It uses preg_match_all as simbabque described

<?php

$html = '<tr class="aaa"><td class="bbb">221.86.2.163</td><td>443</td><td><div><span class="ccc"></span> example <span> example</span></div></td></tr><tr class="aaa"><td class="bbb">221.86.2.163</td><td>443</td><td><div><span class="ccc"></span> example <span> example</span></div></td></tr>';

preg_match_all('|td class="bbb">([\d.]+)</td><td>(\d+)</td>|', $html, $out, PREG_SET_ORDER);

foreach ( $out as $item ) {
    echo "$item[1]:$item[2]\n";
}

?>

output

221.86.2.163:443
221.86.2.163:443

Answer 2

The PHP function preg_match() returns an integer that indicates if it matched. You are only looking at that return value in your loop, so that condition will always be true. That's why you have an infinite loop.

Since preg_match's $matches only gives you all capture groups from matching once, you only get the first match when used with an if.

The Perl code has the /g modifier on the regular expression match, which makes the match global. The match operator =~ returns a true value for each match. It's basically an iterator, so the while loop will go through all matches without repeating a match, so there is no infinite lop. Then the match variables $1 and $2 are used to display results. You need to use preg_match_all to get a global match in PHP.

You need to first match, then iterate the array with the matches. Since the first element is the full match, you can ignore that.

preg_match_all('/td class=\"bbb\">(.*?)<\/td><td>(\d+)<\/td>/',$html,$out);
for ($i = 1; $i < count($out) - 1; $i += 2) {
    echo "$out[$i]:";
    echo $out[$i+1];
    echo "\n";
}