Question

我编写了一个脚本，它从html字符串中获取特定元素。一切正常，而脚本获得不必要的价值。我只想下载第二个值（。*？）。如何修改表达式以仅获取第二个值跳过其余值？。

我的剧本：

<?php
$html = '
<tr><td>AD - Andorra<td>CA - Canada
<tr><td>AE - United Arab Emirates<td>PR - Puerto Rico
<tr><td>AF - Afghanistan<td>US - United States of America
<tr><td>AG - Antigua and Barbuda<td>
';
preg_match_all('/<td>(.*?)<td>(.*?)\n/s', $html, $value);
print_r($value);
?>

Answer 1

虽然有很多方法可以让这只猫受到伤害，而且大多数人会坚持认为正则表达式解决方案是绝对禁止的，但在我看来，你已经存在，你的代码会在{{1}产生正确的结果 - 一个包含第二个捕获括号的值的数组。这是执行代码的psysh会话 -

$value[2]

您可以修改正则表达式以仅捕获第二列，方法是将第一列转换为非捕获括号>>> $html = ' <tr><td>AD - Andorra<td>CA - Canada <tr><td>AE - United Arab Emirates<td>PR - Puerto Rico <tr><td>AF - Afghanistan<td>US - United States of America <tr><td>AG - Antigua and Barbuda<td> ; preg_match_all('/<td>(.*?)<td>(.*?)\n/s', $html, $value); print_r($value); ... ... ... ... ... => """ \n <tr><td>AD - Andorra<td>CA - Canada\n <tr><td>AE - United Arab Emirates<td>PR - Puerto Rico\n <tr><td>AF - Afghanistan<td>US - United States of America\n <tr><td>AG - Antigua and Barbuda<td>\n """ >>> => 4 >>> Array ( [0] => Array ( [0] => <td>AD - Andorra<td>CA - Canada [1] => <td>AE - United Arab Emirates<td>PR - Puerto Rico [2] => <td>AF - Afghanistan<td>US - United States of America [3] => <td>AG - Antigua and Barbuda<td> ) [1] => Array ( [0] => AD - Andorra [1] => AE - United Arab Emirates [2] => AF - Afghanistan [3] => AG - Antigua and Barbuda ) [2] => Array ( [0] => CA - Canada [1] => PR - Puerto Rico [2] => US - United States of America [3] => ) ) => true :(注意第一次打开'/<td>(?:.*?)<td>(.*?)\n/s'后添加的?:。期望的结果位于(然后。修改后的代码执行：

$value[1]

Answer 2

您可以将字符串拆分为数组。 http://php.net/manual/en/function.explode.php

跳过preg_match_all中的值

2 个答案: