如何将＆字符转换为HTML字符？

<?php echo "Hello World!"; ?>

should be:

<?php echo "Hello World!"; ?>

How do I do that in PHP?

You need one of these:

html_entity_decode()
htmlspecialchars_decode()

• html_entity_decode() in PHP Manual
• htmlspecialchars_decode() in PHP Manual

The main difference is that html_entity_decode() will translate all the HTML entities in your string (< becomes <, á becomes á, etc.) while html_specialchars_decode() only translates some special HTML entities:

The converted entities are: &, " (when ENT_NOQUOTES is not set), ' (when ENT_QUOTES is set), < and >.

htmlspecialchars_decode()

Are you looking for html_entity_decode?

If you're actually trying to do this manually, instead of with html_entity_decode, try str_replace.

$needle = array("<",">");
$replace = array("<", ">");
$string = '&lt;?php echo "Hello World!"; ?&gt;';

$string = str_replace($needle, $replace, $string);

print $string; // prints <?php echo "Hello World!"; ?>