使用preg_replace在頁面上查找所有圖像

Question

如何使用「preg_replace」查找所有圖像鏈接？我一直很難理解如何實現正則表達式

是我到目前爲止已經試過：

$pattern = '~(http://pics.-[^0-9]*.jpg)(http://pics.-[^0-9]*.jpg)(</a>)~'; 
$result = preg_replace($pattern, '$2', $content); 

Answer 1

preg_replace()，顧名思義，替換的東西。您想使用preg_match_all()。

<?php 
// The \\2 is an example of backreferencing. This tells pcre that 
// it must match the second set of parentheses in the regular expression 
// itself, which would be the ([\w]+) in this case. The extra backslash is 
// required because the string is in double quotes. 
$html = "<b>bold text</b><a href=howdy.html>click me</a>"; 

preg_match_all("/(<([\w]+)[^>]*>)(.*?)(<\/\\2>)/", $html, $matches, PREG_SET_ORDER); 

foreach ($matches as $val) { 
    echo "matched: " . $val[0] . "\n"; 
    echo "part 1: " . $val[1] . "\n"; 
    echo "part 2: " . $val[2] . "\n"; 
    echo "part 3: " . $val[3] . "\n"; 
    echo "part 4: " . $val[4] . "\n\n"; 
} 

Answer 2

另一種簡單的方法來查找所有圖片來自網頁的鏈接，使用簡單的HTML DOM解析器

// URL從創建DOM或文件

$html = file_get_html('http://www.google.com/'); 

//查找所有圖片

foreach($html->find('img') as $element) 
echo $element->src . '<br>'; 

這是如此簡單的方式來獲得從任何網頁的所有圖像鏈接。