remove items from array if prefix isnt contained in the item

Question

I'm trying to remove all URLs in my array $links which don't start with the prefix in $mustcontain.

Edit: For some reason stackoverflow doesn't permit http://www. so I substituted it with url

Code:

// url prefix each link must start with
$mustcontain = 'url/sub/dir/';

//  Check each link
foreach ( $links as $key => $text )  
{
//  Search $links to make sure it starts with $mustcontain
foreach ( $mustcontain as $goodlink )
{
    if ( stristr( $text, $goodlink ) )
    {
        //  Remove links which dont start with the prefix
            unset( $links[$key] );
        }
    }
}

Example: Based on the criteria above of $mustcontain = 'url/sub/dir/'; The ones I marked should be kept.:

$links = array (
  0 => 'url/sub/dir/1234', // keep
  1 => 'url/sub/dir/', // keep
  2 => 'url/13214124',
  3 => 'url/sub/123123123123',
);

Because I'm totally clueless when it comes to dealing with arrays — michelleisconfused, Jun 30 '16 at 17:48
But `$mustcontain` is a string and not an array? This should throw an error. — M. Eriksson, Jun 30 '16 at 17:51
Using a code from [startsWith() and endsWith() functions in PHP](http://stackoverflow.com/q/834303/4577762), take a look at [https://3v4l.org/5gtqe](https://3v4l.org/5gtqe) — FirstOne, Jun 30 '16 at 17:51
If you want a regex approach: https://3v4l.org/qZ1VJ @MagnusEriksson how did you post when it's duplicated haha — Matt, Jun 30 '16 at 17:59

M. Eriksson · Accepted Answer · 2016-06-30T18:01:30.877

3

This is how I would do it:

// url prefix each link must start with
$mustcontain = 'url/sub/dir/';

//  Check each link
foreach ( $links as $key => $text )  
{
    if (strpos($text, $mustcontain) !== 0) {
        // $mustcontain wasn't found in the beginning of $text
        // so unset that element from the array.
        unset($links[$key]);
    }
}

We're using !== for strict checking, since 0 (which is what we want) and false (which we don't want) would evaluate as false otherwise.

edited Jun 30 '16 at 18:01

answered Jun 30 '16 at 17:57

M. Eriksson

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Change your condition, right now your code is removing everything. You should check if `strpos` returns `false` : `if (strpos($text, $mustcontain) === false) {` – Jose Manuel Abarca Rodríguez Jun 30 '16 at 18:04
Nope. `!== 0` means that if we don't find `$mustcontain` on the position `0` (the start of the string) we remove the element, since OP said: "which don't start with $mustcontain" – M. Eriksson Jun 30 '16 at 18:04
I'm running your code right now, aren't you running it? – Jose Manuel Abarca Rodríguez Jun 30 '16 at 18:04
Use `print_r` with the resulting array and see. – Jose Manuel Abarca Rodríguez Jun 30 '16 at 18:06
If you test with his `$links` array, then yes.. because none of them starts with the examples `$mustcontain` - But the question was only to remove all links that doesn't start with the `$mustcontain` variable. – M. Eriksson Jun 30 '16 at 18:10
..you need to remove the `**` from his array, he was trying to bold it. :) @JoseManuelAbarcaRodríguez – M. Eriksson Jun 30 '16 at 18:14

remove items from array if prefix isnt contained in the item

1 Answers1