php array: return matching elements

Question

 class Photos 
{
private $photos = array();

function add_photo($filename, $date, $lat, $long) 
{
  $this->photos[] = array('filename' => $filename, 'date' => $date, 'lat' => $lat,  'long' => $long);
    return $this;
}

function get_all() 
{
   return json_encode($this->photos);
}

function get_N($n) 
{
    return json_encode(array_slice($this->photos, 0, $n));
}

}

I would like another function in my class that returns some of the arrays with a certain date. The date is extracted from photos using the exif_read_data function. They look something liek this: 2011:04:01 16:12:23. The function that im looking for should return all the photos from a certain date. So i would like to know how i make the function return, for example, all photos with a datestamp looking like 2011:04:01 xx:xx:xx. Hope you understand what i mean. Thanks in advance!

Alix Axel · Accepted Answer · 2011-04-25 23:39:17Z

1

This should do it:

class Photos 
{
    private $photos = array();

    function add_photo($filename, $date, $lat, $long) { /* ... */ }

    function get_all() { /* ... */ }

    function get_N($n) { /* ... */ }

    function get_by_date($date)
    {
        $result = array();

        foreach ($this->photos as $photo)
        {
            if (strpos($photo['date'], $date) === 0)
            {
                $result[] = $photo;
            }
        }

        return $result;
    }
}

Photos::get_by_date('2011:04:01');

You may also want to look at the array_filter() function.

function get_all_dates()
{
    $result = array();

    foreach ($this->photos as $photo)
    {
        $result[substr($photo['date'], 0, 10)] = null;
    }

    return array_keys($result);
}

function get_all_dates_with_count()
{
    $result = array();

    foreach ($this->photos as $photo)
    {
        $date = substr($photo['date'], 0, 10);

        if (empty($result[$date]))
        {
            $result[$date] = 0;
        }

        ++$result[$date];
    }

    return $result;
}

edited Apr 25, 2011 at 23:39

answered Apr 25, 2011 at 21:07

Alix Axel

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5 Comments

Compeek Over a year ago

Good note about the array_filter() function, but that would effectively be the same as just doing what you have here. You'll end up writing a function comparing the date anyway.

Alix Axel Over a year ago

@Compeek: In PHP 5.3 you can define lambda functions, but yeah. I just mentioned because the OP might want to perform similar filters on his data. :)

Compeek Over a year ago

Never hurts to give an answer with bonus info. :)

Berntsson Over a year ago

hmm, followup question: is there any way to make a function that returns all the dates that contains any photos?

Berntsson Over a year ago

btw, how do i count the number of photos for each date? i would like to return a count with each date.

Compeek · Accepted Answer · 2011-04-25 21:07:41Z

0

function get_by_date($date) {
    $date = strftime('%D', strtotime($date));
    $photos = array();
    foreach($this->photos as $photo) {
        if(strftime('%D', strtotime($photo['date'])) == $date) {
            $photos[] = $photo;
        }
    }
    return $photos;
}

answered Apr 25, 2011 at 21:07

Compeek

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Comments

NikiC · Accepted Answer · 2011-04-25 21:09:25Z

0

I would simply check if the first 10 characters are the same:

public function getByDate($date) {
    $return = array();
    foreach ($this->photos as $photo) {
        if ($date == substr($photo['date'], 0, 10)) {
            $return[] = $photo;
        }
    }

    return $return;
}

If you are on PHP 5.3 you could do this using array_filter and a Closure:

public function getByDate($date) {
    return array_filter($this->photos, function($photo) use($date) {
        return $date == substr($photo['date'], 0, 10);
    });
}

answered Apr 25, 2011 at 21:09

NikiC

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