如何安全地检查节点是否为空?(Symfony 2 爬虫)

本文介绍了如何安全地检查节点是否为空?(Symfony 2 爬虫)的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

当我尝试从页面中获取一些不存在的内容时，我发现了这个错误:

When I try to take some nonexistent content from page I catch this error:

The current node list is empty. 500 Internal Server Error - InvalidArgumentException

如何安全地检查此内容是否存在?这里有一些不起作用的例子:

How can I safely check exists this content or not? Here some examples that does not work:

if($crawler->filter('.PropertyBody')->eq(2)->text()){ // bla bla } if(!empty($crawler->filter('.PropertyBody')->eq(2)->text())){ // bla bla } if(($crawler->filter('.PropertyBody')->eq(2)->text()) != null){ // bla bla }

谢谢，我帮助了自己:

$count = $crawler->filter('.PropertyBody')->count(); if($count > 2){ $marks = $crawler->filter('.PropertyBody')->eq(2)->text(); }

推荐答案

你有没有尝试过这样的事情?

Have you tried something like this?

$text = null; if (!empty($body = $crawler->filter('.PropertyBody'))) { if (!empty($node = $body->eq(2))) { $text = $node->text(); } } $this->assertContains('yourText', $text);