CODEWITHSUNDEEP
phpregexstringdomsubstring
user3182138
user3182138

Reputation:

Replace substrings between tags in a string in php

I have been working on this for whole day but couldn't find a solution in which I can replace substrings in string in php like I have string

'<div>
   <h2>this is <span>String</span> found in h2 tag</h2>
   <p>Hello World</p>
   <h2>this is <span>String</span> found in h2 tag</h2>
   <p>Hello Universe</p>
   <h2>this is <span>String</span> found in h2 tag</h2>
</div>'

I want to get every string inside h2 and then perform some htmlentity replacement like

$str = 'this is <span>String</span> found in h2 tag';
$sanitized = htmlspecialchars($str,ENT_QUOTES);

and then output complete string but replaced.

How it can be done?

<div>
    <h2>this is &lt;span&gt;String&lt;/span&gt; found in h2 tag</h2>
    <p><b>Hello</b> World</p>
    <h3>this is <span>String</span> found in h2 tag</h3>
    <p><b>hello</b> Universe</p>
    <h2>this is &lt;span&gt;String&lt;/span&gt; found in h2 tag</h2>
</div>

Upvotes: 0

Views: 688

Answers (1)

Mika Tuupola
Mika Tuupola

Reputation: 20387

You can use preg_replace_callback(). Regular expression for matching <h2> tags is :

/<h2>(.+?)<\/h2>/

If you would like to match all <hx>tags instead use the following instead:

/<h([1-6])(.*?)<\/h\1>/

In callback function you can alter the matched string. For example:

$html = <<< EOH

<div>
   <h2>this is <span>String</span> found in h2 tag</h2>
   <p>Hello World</p>
   <h2>this is <span>String</span> found in h2 tag</h2>
   <p>Hello Universe</p>
   <h2>this is <span>String</span> found in h2 tag</h2>
</div>

EOH;

$html = preg_replace_callback("/<h2>(.+?)<\/h2>/", function($matches) {
    /* Convert content of <h2> tags to HTML entities. */
    $altered =  htmlspecialchars($matches[1], ENT_QUOTES);

    /* Put the converted content back inside <h2> tag and return it. */
    return str_replace($matches[1], $altered, $matches[0]);
}, $html);

$html = preg_replace_callback("/<p>(.+?)<\/p>/", function($matches) {
    /* Make match bold. */
    $altered = "<b>" . $matches[1] . "</b>";

    /* Put the converted content back inside <p> tag and return it. */
    return str_replace($matches[1], $altered, $matches[0]);
}, $html);

print $html;

Output of the above script is:

<div>
   <h2>this is &lt;span&gt;String&lt;/span&gt; found in h2 tag</h2>
   <p><b>Hello World</b></p>
   <h2>this is &lt;span&gt;String&lt;/span&gt; found in h2 tag</h2>
   <p><b>Hello Universe</b></p>
   <h2>this is &lt;span&gt;String&lt;/span&gt; found in h2 tag</h2>
</div>

Upvotes: 3

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