array_rand not working correctly?

Question

I want to show different content on each page refresh. To accomplish this, I've used the PHP array_rand() function.

I fetched posts and stored content in a value using the below code. When I output the value before array_rand(), it is showing first post content but in array_rand() if I output the random functionality is working but showing some random number. I believe it's post count. The minimum num shown is 0 and max is 2 there are 3 posts.

Check this here and the code I used is.

<?php
    $args = array(
        'posts_per_page' => '-1',
        'order'=> 'ASC',
        'orderby'=>'menu_order',
        'paged' => $paged,
        'post_type' => 'Didyouknows' 
    );

    $loop = new WP_Query( $args );
    $posts = $loop->get_posts();

    foreach($posts as $post){
        //print_r($loop);exit;
        //echo $loop->['ID'];

        $rval[]= $post->post_content;

        //print_r($rval);exit;
        //echo $loop[post_content];
        //print_r($rval);exit;

        $rand = array_rand($rval);
        //echo $rval[$rand[0]];
        //echo $rand;
    }
?>

<h2><?php echo $rand; ?></h2>

Where am I going wrong?

Answer 1

Getting a single random post would be far more efficient than getting all posts, then plucking a random post from the query. Here's an updated WP_Query instance using 'orderby' => rand:

$args = array( 
    'orderby' => 'rand',
    'posts_per_page' => '1',
    'paged' => $paged,
    'post_type' => 'Didyouknows', // Post type names should never use capital letters, btw 
);

$loop = new WP_Query( $args );

if ( $loop->have_posts() ) {
    while ( $loop->have_posts() ) { $loop->the_post(); ?>
        <h2><?php the_content(); ?></h2><?php
    }
}
wp_reset_postdata();

In your original code, you are seeing the values of 0, 1, and 2 which represent the possible keys for elements within your $rval array. You should move $rand = array_rand($rval); out of the foreach loop and do something like:

<h2><?php echo $rval[ $rand ]; ?></h2>

The fist solution using WP_Query and 'orderby' => 'rand' is preferable though.