php将字符串替换为html标记

Question

I want to display content in a php page from a .txt and change some tag to a html code like the following using:

Change this:

[img: something.jpg]

To this:

<img src="something.jpg" />  

I've tried to use preg_replace, but I have no idea how to use those symbols like /(){}^*.:. What it means to use things like this to extract some variables $1 $2 from a string?

$string = 'April 15, 2003';
$pattern = '/(\w+) (\d+), (\d+)/i';

Answer 1

You can use the following regex like as

\[(\w+):\s?(\w+.\w+)]

Regex Explanation

• \[ : \[ will check for [ literally.
• (\w+): : (\w+) Capturing groups of any word character [a-zA-Z0-9_]. + Between one and unlimited times, as many times as possible, : will check for : literally
• \s? : match any white space character [ \t\f ]. ? Between zero and one time, as many times as possible
• (\w+.\w+) : Capturing group of any word character [a-zA-Z0-9_]

So using preg_replace like as

echo preg_replace('/\[(\w+):\s?(\w+.\w+)]/',"<$1 src='$2' />","[img: something.jpg]");

Regex

Demo