PHP what is difference between multidimensional array and simple array?

Question

For example i did this code

<?php
$arr= [12, 24,17,49];
foreach ($arr as $value) {
    if ($value % 2 == 0) 
        $max = $value + 1;
    else
        $max = $value - 1;
    var_dump($max);
    echo $max;
}
?>

it works perfectly but why when it comes to multidimensional arrays like these:

<?php
$arr= array (
    array (12, 24, 17, 49 ),
    array (10, 4, 99, 74)
);
foreach ($arr as $value) {
    if ($value % 2 == 0) 
        $max = $value + 1;
    else
        $max = $value - 1;
    var_dump($value);
    echo $value;
}
?>

Code just wont work,tried alot of variations, dont know what clue i am missing.

$value is an array in the second example because it is multi-dimensional. The foreach goes 1 level in so on the first one your get 12 then 24, etc. On the second on you get array (12, 24, 17, 49 ) then array (10, 4, 99, 74). — user3783243
– user3783243, Commented Jun 27, 2018 at 21:06
as well as the answer below you might want to look in to "recursive" functions — user9487972
– user9487972, Commented Jun 27, 2018 at 21:17
It may be helpful if you add a brief description of what the code is supposed to do. — Don't Panic
– Don't Panic, Commented Jun 27, 2018 at 21:35
A good way to get a visual of this would be to print_r($value), and you will see that $value is an array with 4 elements in it. — L1R
– L1R, Commented Jun 27, 2018 at 21:43

Ylber Veliu · Accepted Answer · 2018-06-27 21:05:30Z

1

You have to go one level deeper because you have nested arrays in an array

Your code will be

 $arr= array(
       array (12, 24, 17, 49 ),
       array (10, 4, 99, 74)
     );

foreach ($arr as $inner_arr) 
{
   foreach ($inner_arr as $value) 
   {
     if ($value % 2 == 0) 
       $max = $value + 1;
     else
       $max = $value - 1;

     echo $value ."<br />";
   }
 }

echo $max;

Read more at about multidimensional arrays here http://php.net/manual/en/language.types.array.php

answered Jun 27, 2018 at 21:05

Ylber Veliu

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1 Comment

L1R Over a year ago

This is it. your first foreach loop's $value is equal to your first questions $arr.

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