php foreach as key, every two number as a group

Question

<?php
$data=array('1','2','3','4','5','6','7','8','9','10','11');
foreach($data as $key=> $element){
    if($key % 2 != 0){
        echo $element.'<br />';
    }
    echo '<hr />';
}
?>

php foreach as key, how to make every two number as a group?

I want to output:

1,2
_____
3,4
_____
5,6
_____
7,8
_____
9,10
_____
11

Lamonicalamont

Answer 1

Have a look at the array_chunk() function.

In your case you'd use it like this:

foreach(array_chunk($data, 2) as $values) {
    echo implode(',', $values)."\n";
}

During the last iteration $values will have only one element so if you plan to access the elements directly using their index remember to use count() to check the array's element count.

Teddman

Answer 2

Your foreach() is fine but you want to print every element, not just every even one. You also don't want the horizontal rule every time either, just every even. Thus:

<?php
$data=array('1','2','3','4','5','6','7','8','9','10','11');
foreach($data as $key=> $element){
    echo $element;
    if($key % 2 != 0){
        echo "<br/><hr />";
    }
    else {
        echo ",";
    }
}
?>

Trustbuster

Answer 3

Here's a functional-style script. array_chunk() with produce sets of elements with a count no larger than the nominated size. implode() will only insert the delimiting string if it is necessary.

Code: (Demo)

$data = range(1, 11);

echo implode(
    "\n",
    array_map(
        fn($chunk) => implode(', ', $chunk),
        array_chunk($data, 2)
    )
);

Output:

1, 2
3, 4
5, 6
7, 8
9, 10
11

Soapwort