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Question

I have a problem with a piece of XML that I want to parse with PHP. Here is the example I have:

<tags>
    <content>content</content>
    <amplifications>
        <tag>content 1</tag>
    </amplifications>
    <amplifications>
        <tag>content 2</tag>
        <tag>content 3</tag>
        <tag>content 4</tag>
        <tag>content 5</tag>
    </amplifications>
</tags>

Where I want to remove

</amplifications>
<amplifications>

I've tried using preg_replace, but it seems that I cannot figure it out because those tags are indented differently and there are whitespaces.

Answer 1

这应该可以帮到你。

str_replace("</", "<", $XMLData);

Answer 2

The first problem you might encounter is that preg_replace isn't matching between different lines by default.

You can add a modifier ( http://php.net/manual/en/reference.pcre.pattern.modifiers.php ) to change this.

m (PCRE_MULTILINE)

By default, PCRE treats the subject string as consisting of a single "line" of characters (even if it actually contains several newlines). The "start of line" metacharacter (^) matches only at the start of the string, while the "end of line" metacharacter ($) matches only at the end of the string, or before a terminating newline (unless D modifier is set). This is the same as Perl. When this modifier is set, the "start of line" and "end of line" constructs match immediately following or immediately before any newline in the subject string, respectively, as well as at the very start and end. This is equivalent to Perl's /m modifier. If there are no "\\n" characters in a subject string, or no occurrences of ^ or $ in a pattern, setting this modifier has no effect.

After that, you have to be carefull while writing your regexp. Things like that could happen:

<amplifications>
    <amplifications>
    </amplifications>
</amplifications>

And you don't want to match the first <amplifications> with the first </amplifications> . If this case can't happen, your regexp will be easier to write.

I can add details if you want to, but that should already help you a bit.

Answer 3

Merge all children of all elements with a specific tag-name into the first element:

Example XML:

<tags>
    <content>content</content>
    <amplifications>
        <tag>content 1</tag>
    </amplifications>
    <amplifications>
        <tag>content 2</tag>
        <tag>content 3</tag>
        <tag>content 4</tag>
        <tag>content 5</tag>
    </amplifications>
</tags>

PHP-Example:

$doc = new DOMDocument();
$doc->formatOutput = true;
$doc->preserveWhiteSpace = false;
$doc->loadXML($xml);

$name     = 'amplifications';
$elements = $doc->getElementsByTagName($name);

foreach ($elements as $parent) {
    if ($elements->item(0) === $parent) {
        continue;
    }
    foreach (iterator_to_array($parent->childNodes) as $child) {
        $elements->item(0)->appendChild($child);
    }
    $parent->parentNode->removeChild($parent);
}

echo $doc->saveXML();

Output:

<?xml version="1.0"?>
<tags>
  <content>content</content>
  <amplifications>
    <tag>content 1</tag>
    <tag>content 2</tag>
    <tag>content 3</tag>
    <tag>content 4</tag>
    <tag>content 5</tag>
  </amplifications>
</tags>