Is there a more efficient way to extract links from an array of strings?

Question

I run (Real Estate RETS) queries that will only return objects. The contents of these objects appear to be strings that contain different types of information about sets of images (ie. several different pictures from the same house). All I want is the link to each picture ("Location:" in the sample below), put into an array that I can use elsewhere in the script.

I have figured out how to accomplish this using a nested set of explode() commands, but I was wondering if there is a more direct, efficient way to do this: something like ltrim(delete everything to the end of the word "Location: "), and then rtrim(delete everything after ".jpg") leaving me with each value in an array like $picturelinks.

Here is a sample of the data I'd like to do this with.

Array (
    [1] => WhateverGibberish
    Content-Type: image/jpeg
    Content-ID: bunchofnumbers
    Object-ID: 1
    Location: http://cdn.photos.sparkplatform.com/met/347305719000000-o.jpg
    Content-Description: Welcome
    Preferred: 1
    
    [2] => WhateverGibberish
    Content-Type: image/jpeg
    Content-ID: bunchofnumbers
    Object-ID: 2
    Location: http://cdn.photos.sparkplatform.com/met/350148712000000-o.jpg
    Content-Description: Welcome home
    
    [3] => WhateverGibberish
    Content-Type: image/jpeg
    Content-ID: bunchofnumbers
    Object-ID: 3
    Location: http://cdn.photos.sparkplatform.com/met/351982042000000-o.jpg
    Content-Description: Brick

    [4] => WhateverGibberish
    Content-Type: image/jpeg
    Content-ID: bunchofnumbers
    Object-ID: 4
    Location: http://cdn.photos.sparkplatform.com/met/353549178000000-o.jpg
    Content-Description: Brix
)

Here is the php code that does accomplish the task, but I wonder if there is a method that would run faster:

<?php
$photos = $rets->GetObject("Property", "HiRes", $sysid, "*", 1); //1 gets links
foreach($photos as $photo) { //array includes everything for all photos      
    unset ($photo['Success']); //not needed
    unset ($photo['Content-Type']); //not needed
    unset ($photo['Length']); //not needed
        
    $pile=explode('--',$photo['Data']);
    unset ($pile[0]);
    foreach ($pile as $blah) {
        $subpile=explode('Location: ',$blah);
        $picstuff[]=$subpile[1];
    }
    foreach($picstuff as $piclilnk) {
        $breakme=explode('Content-Description: ',$piclilnk);
        $linksonly[]=$breakme[0];
        $otherstuff[]=$breakme[1];
    }
    //print_r($linksonly);
    //print_r($otherstuff);
?>

Please 1) show us the actual code you wrote, rather than just describing it. Then it'll be a lot easier to tell you if there's another way to do it. 2) provide the sample data in code format (you can use var_export() to get it out of your application if necessary) so it can easily be re-used in answers and experiments without tedious re-keying being needed by those who might want to help you, and 3) define what exactly you mean by "efficient". What's your metric? Less code? Runs faster? Fewer function calls? Is your current method causing a specific problem? Please edit your post. Thanks. — ADyson
– ADyson, Commented Mar 27 at 22:22
Thanks. Data format could still be made easier for us to re-use. Also, how fast does this run currently, for given sizes of array? Is the speed giving you problems? How much of an improvement would be useful? — ADyson
– ADyson, Commented Mar 27 at 23:24
WOW! preg_match('/^\slocation:\s*(.)/im', $p, $match)) worked great! I added microtime() to completely stripped down versions of the query script (one with my explodes() and the other with preg_match() and tested each five times. Nested explodes() version: 2.2705860137939 2.2768650054932 0.53050899505615 0.9162609577179 0.95514106750488 Pregmatch version: 0.58952713012695 0.59466981887817 0.51377582550049 0.49790787696838 0.52830195426941 — phc_joe
– phc_joe, Commented Mar 28 at 15:07
Why all the down votes for this question? I did a careful search prior to posting and did not find anything that I understood clearly enough to apply. Many thanks to those who did bother to help! — phc_joe
– phc_joe, Commented Mar 28 at 15:17

Barmar · Accepted Answer · 2025-03-27 23:48:36Z

2

Use a regular expression to find the lines that begin with Location: and extract the rest of the line using a capture group.

foreach ($pile as $p) {
    if (preg_match('/^\s*location:\s*(.*)/im', $p, $match)) {
        $linksonly[] = $match[1];
    }
}

If you need other values you can extract them similarly.

answered Mar 27 at 23:48

Barmar

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1 Comment

phc_joe Mar 28 at 15:14

Thank you! I tried this out and it seems to cut the process time by about 50-75% most of the time.

Pedro Amaral Couto · Accepted Answer · 2025-03-28 00:24:03Z

1

Let's suppose $pile is the array you mentioned (after "Here is a sample of the data I'd like to do this with.").

You can list all the strings next to "Location:" in the same line using a regex like this:

$picturelinks = array_map(
    function($string) {
    preg_match('/^Location:\s*([^\r\n]+)/m', $string, $matches);
    return $matches[1] ?? null;
    },
    $pile
);

But I suppose you can parse $photo['Data'] once:

preg_match_all('/^Location:\s*([^\r\n]+)/m', $photo['Data'], $matches);
$picturelinks = $matches[1] ?? [];

I tested it using: https://onlinephp.io/

answered Mar 28 at 0:24

Pedro Amaral Couto

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