Join array with a comma every two elements

Question

I have an array

$str = $query->get_title(); //Red blue yellow dog cat fish mountain
$arr = explode(" ",$str);

//output of $arr
Array
(
    [0] => Red 
    [1] => blue 
    [2] => yellow 
    [3] => dog 
    [4] => cat 
    [5] => fish 
    [6] => mountain
)

Now I want to join the above array with , every two words. The expected result is as below

$result = "Red blue, yellow dog, cat fish, mountain";

How can I do that?

Answer 1

Please try this, it uses array_chuck, explode, and implode.

<?php

$str = "Red blue yellow dog cat fish mountain";

$result = implode(', ', array_map(function($arr) {
    return implode(' ', $arr);
}, array_chunk(explode(' ', $str), 2)));

echo $result;

Output: Red blue, yellow dog, cat fish, mountain

---

Another method using a forloop if you don't like nested methods.

<?php

$str = "Red blue yellow dog cat fish mountain";

$words = explode(' ', $str);

foreach ($words as $index => &$word)
    if ($index % 2)
        $word .= ',';

$result = implode(' ', $words);

echo $result;

Output: Red blue, yellow dog, cat fish, mountain