Find next and preview element in array

Question

I am beginner in PHP.

I have this array:

$array = array(
    ['name' => 'project 1', 'url' => 'www.name1.com', 'photo' => '1.jpg'],
    ['name' => 'project 2', 'url' => 'www.name2.com', 'photo' => '2.jpg'],
    ['name' => 'project 3', 'url' => 'www.name3.com', 'photo' => '3.jpg'],
    ['name' => 'project 4', 'url' => 'www.name4.com', 'photo' => '4.jpg'],
    ['name' => 'project 5', 'url' => 'www.name5.com', 'photo' => '5.jpg'],
    ['name' => 'project 6', 'url' => 'www.name6.com', 'photo' => '6.jpg'],
)

I need get by function next and previous element from my array (if exist):

$next = next($actualUrl);
$previous = previous($actualUrl);

How can I make it?

maybe that helps https://stackoverflow.com/questions/795625/how-to-set-an-arrays-internal-pointer-to-a-specific-position-php-xml — FatFreddy, Aug 21 '20 at 08:22

GNassro · Accepted Answer · 2020-08-21T15:34:11.697

this simple code will help you:

<?php

function next_elm ($array, $actualUrl) {
    $i = 0;
    while ( $i < count($array) && $array[$i]["url"] != $actualUrl ) $i++;  
    
   if ($i < (count($array) - 1)) {
       return $array[$i+1];
   } else if ($i == (count($array) - 1)) {
       return $array[0];  // this is depend what you want to return if the url is the last element
   } else {
       return false; // there is no url match
   }
    
}
function prev_elm ($array, $actualUrl) {
    $i = 0;
    while ( $i < count($array) && $array[$i]["url"] != $actualUrl ) $i++;  
    
   if ($i < (count($array)) && $i>0) {
       return $array[$i-1];
   } else if ($i == 0) {
       return $array[count($array) - 1];  // this is depend what you want to return if the url is the first element
   } else {
       return false; // there is no url match
   }
    
}

score 0 · Answer 2 · edited Aug 21 '20 at 08:10

0

I prefer to iterate over any array via a foreach loop. if you want anything specific out of it just copy it into a tmp variable. for example:

$tmp_var = null;
foreach($array as $key => $value){
   $tmp_var = $value['name'];
}

edited Aug 21 '20 at 08:10

Dharman

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answered Aug 21 '20 at 08:05

Niklas Schäffer

9
2

So how would you deal with previous and next items? – Nigel Ren Aug 21 '20 at 08:09
I always can add an additional if clause in my foreach right. So why even bother with next and previous in the first place ? – Niklas Schäffer Aug 21 '20 at 08:14
3

As that was the requirement in the original question then it sounds as though it's an important part of the answer to show how to do this. – Nigel Ren Aug 21 '20 at 08:15

score 0 · Answer 3 · answered Aug 21 '20 at 08:31

First find actual url, then use this index to find previous and next items. Also you should add checks if the current item is first or last element to avoid null pointer exception.

$curr = 0;
foreach($array as $value){
    if($value['url'] == 'www.name2.com'){
        break;
    }
    $curr += 1;
}

$previous = $array[$curr-1];
$next = $array[$curr+1];

Find next and preview element in array

3 Answers3