Extract content from each first TD in a Table

问题

I've got some HTML that looks like this:

<tr class="row-even">
    <td align="center">abcde</td>
    <td align="center"><a href="deluserconfirm.html?user=abcde"><img src="../images/delete_x.gif" alt="Delete User" border="none" /></a></td>
</tr>
<tr class="row-odd">
    <td align="center">efgh</td>
    <td align="center"><a href="deluserconfirm.html?user=efgh"><img src="../images/delete_x.gif" alt="Delete User" border="none" /></a></td>
</tr>
<tr class="row-even">
    <td align="center">ijkl</td>
    <td align="center"><a href="deluserconfirm.html?user=ijkl"><img src="../images/delete_x.gif" alt="Delete User" border="none" /></a></td>
</tr>

And I need to retrieve the values, abcde, efgh, and ijkl

This is the regex I'm currently using:

preg_match_all('/(<tr class="row-even">|<tr class="row-odd">)<td align="center">(.*)<\/td><\/tr>/xs', $html, $matches);

Yes, I'm not very good at them. As with most of my regex attempts, this is not working. Can anyone tell me why?

Also, I know about html/xml parsers, but it would require a significant code revisit to make that happen. So that's for later. We need to stick with regex for now.

EDIT: To clarify, I need the values between the first <td align="center"></td> tag after either <tr class="row-even"> or <tr class="row-odd">

回答1:

~<tr class="row-(even|odd)">\s*<td align="center">(.*?)</td>~m

Notice the m modifier and the use of \s*.

Also, you can make the first group non-capturing via ?:. I.e., (?:even|odd) as you're probably not interested in the class attribute :)

回答2:

Try this:

preg_match_all('/(?:<tr class="row-even">|<tr class="row-odd">).<td align="center">(.*?)<\/td>/s', $html, $matches);

Changes made:

You've not accounted for the newline between the tags
You don't need to x modifier as it will discard the space in the regex.
Make the matching non-greedy by using .*? in place of .*.

Working link

回答3:

Actually, you dont need a too big change in your codebase. Fetching Text Nodes is always the same with DOM and XPath. All that does change is the XPath, so you could wrap the DOM code into a function that replaces your preg_match_all. That would be just a tiny change, e.g.

include_once "dom.php";
$matches = dom_match_all('//tr/td[1]', $html);

where dom.php just contains:

// dom.php
function dom_match_all($query, $html, array $matches = array()) {
    $dom = new DOMDocument;
    libxml_use_internal_errors(TRUE);
    $dom->loadHTML($html);
    libxml_clear_errors();
    $xPath = new DOMXPath($dom);
    foreach( $xPath->query($query) as $node ) {
        $matches[] = $node->nodeValue;
    }
    return $matches;
}

and would return

Array
(
    [0] => abcde
    [1] => efgh
    [2] => ijkl
)

But if you want a Regex, use a Regex. I am just giving ideas.

回答4:

This is what I came up with

<td align="center">([^<]+)</td>

I'll explain. One of the challenges here is what's between the tags could be either the text you're looking for, or an tag. In the regex the [^<]+ says to match one or more characters that is not the < character. That's great, because that means the won't match, and the the group will only match until the tag is found.

回答5:

Disclaimer: Using regexps to parse HTML is dangerous.

To get the innerhtml of the first TD in each TR, use this regexp:

/<tr[^>]*>\s*<td[^>]>(.+?)<\/td>/si

回答6:

This is just a quick and dirty regex to meet your needs. It could easily be cleaned up and optimized, but it's a start.

<tr[^>]+>[^\n]*\n               #Match the opening <tr> tag
  \s*<td[^>]+>([^<]+)[^\n]+\n   #Group the wanted data
  [^\n]+\n                      #Match next line
</tr>                           #Match closing tag

Here is an alternative way, which may be more robust:

deluserconfirm.html\?user=([^"]+)

来源：https://stackoverflow.com/questions/3966033/extract-content-from-each-first-td-in-a-table

标签

php

regex

preg-match-all