Question

如何重复此功能，直到找到我正在寻找的图像类？假设img.header仅存在于给定的一些随机id范围内。请不要使用标题。

<?php

include('simple_html_dom.php');

$randomID = mt_rand(100, 1000);
$url = "http://newspaper.com/article/".$randomID;

// Create DOM from URL or file
$html = file_get_html($url);

//Find img
$element = $html->find('img.header');

//Check if image was found              
if (strpos($element,'img') == false) {
    ///////////////////////////////////////////
    //Repeat until find('img.header') is true//
    ///////////////////////////////////////////
} else {
    echo $element->src;
}

?>

Answer 1

许多可能的方式，一个更简单的例子：

<?php
$ids = range(100, 400000); // RAM is so cheap
shuffle($ids); // still not convinced it makes a difference, but why not...

foreach( $ids as $index=>$id ) {
    // <-- maybe you want to add some output here, so you can see that the script is still running.
    $url = "http://newspaper.com/article/".$id;
    $html = file_get_html($url);
    // edit: <-- some error handling here. See documentation of simple_html_dom on how to check $html for error conditions
    $element = $html->find('img.header');
    if ( $element ) {
        // found it
        // and the ids you've had to visit before finding the element are
        $visited = array_slice($ids, 0, $index+1);  
        break; // no need to go on, exit foreach-loop
    }
}

if ( !isset($visited) ) {
    // the element was never found....
}
else {
    // $html, $element and even $id should be still valid
    // so, you can use them here for further processing
}

重复直到真

1 个答案: