php random order from a foreach

Question

I have some foreach, this could work well

foreach ($umm as $data) {
        echo '<img src="'.$data->picture.'" />';
        echo  $data->id;
}

Now I want shuffle the foreach. I tried:

foreach (shuffle($umm) as $data) {
        echo '<img src="'.$data->picture.'" />';
        echo  $data->id;
}

AND

foreach ($umm as $data) {
        $rand_pic[] = $data->picture;
        $rand_id[] = $data->id;
}
$ran = shuffle($rand_id);
foreach($ran as $new){
    echo '<img src="'.$new->picture.'" width="100" />';
    echo $new->id;
}

All these caused Warning: Invalid argument supplied for foreach() in second foreach. How to random order from a foreach?

Answer 1

Take a look at the documentation for shuffle(). It takes a reference to an array and shuffles it in place. So you need to use it on the array, then iterate:

shuffle($umm);

foreach ($umm as $data) {
        echo '<img src="'.$data->picture.'" />';
        echo  $data->id;
}

Answer 2

shuffle() returns a boolean - you pass the array by reference

Try this:

shuffle($umm);
foreach($umm as $new){
    echo '<img src="'.$new->picture.'" width="100" />';
    echo $new->id;
}