Getting a sub string between two different delimiters

Question

I am trying to "extract" the link part from a tweet message:

$tweet = "Testing a tweet with a link https://t.co/h4C0aobVnK in the middle"

I have a function which doesn't quite work but I'm not sure why. I need to get the link part, so I need everything between https:// and the space

The result I want would be: t.co/h4C0aobVnK

This is the function:

function dataBetween($string, $start, $end){
    $sp = strpos($string, $start)+strlen($start);
    $ep = strpos($string, $end)-strlen($start);
    $data = trim(substr($string, $sp, $ep));
    return trim($data);
}

Here's how it's called:

$link = dataBetween($tweet,'https://',' ');

But the result I get is not what I expected:

t.co/h4C0aobVnK in the middl

Where did I go wrong?

Is there a better way to extract the link part from $tweet ? It will always start with https://.

Answer 1

You should use regular expressions for this. This might look complicated, but once you start using them, there is no going back. ;)

preg_match_all("/https:\/\/(.*?)\s/", $string, $matches);
print_r($matches);

Answer 2

strpos finds the first occurrence of a string. For $ep, you should start looking AFTER the $sp, not from the beginning of the string

$ep = strpos($string, $sp)-strlen($end);

also, you could use a regular expression like this |www://([^ ]+)|i *http is not allowed in the comment box, so just replace ww with that

Answer 3

   $ep = strpos($string, $end)-strlen($start);

change to

$ep = strpos($string, $end)-strlen($end);

Just a misstype.

Answer 4

Use

$regex = "((https?|ftp)\:\/\/)?"; // SCHEME

 if(preg_match("/^$regex$/", $tweet , $m))
  var_dump($m);

Answer 5

Well, change this:

$ep = strpos($string, $end)-strlen($start);

To:

$ep = strpos($string, $end, $sp) - strlen($string);

Passing the third parameter of strpos (offset) it will start from where the link started, and get the first ' ' after that.

Working code