Get latest post from categories

Question

I have 3 categories: Travel, Destination and Tips. I've been trying to get the latest post from each categories then put them into an array. Here's what I have in mind.

//GET CATEGORIES
//I have this code but this only selects one category
$args = array ( 'post_per_page' => 1, 'cat' => 16 ); 

//SELECT THE LATEST POST FROM EVERY CATEGORY
//This part I don't know what to do.

//GET ID OF THE POST SO THAT I CAN ADD IT TO THE ARRAY
$post   = array(); <-- This should contain every latest post from the categories.
$post[] = get_post( /*ID OF THE POST SHOULD BE HERE*/ );

What I want to achieve is to have the id's of the latest posts from every category in the array. Please help. Thank you.

Answer 1

Ok you can use a foreach loop to return the latest post from each category. Here is how you should do that.

<?php

    $postids = array();
    $catids = array( 1, 2, 3 ); // add category ids here.

    foreach ( $catids as $catid ) {

        $my_query = new WP_Query( array( 'cat' => $catid, 'ignore_sticky_posts' => 1, 'posts_per_page' => 1, 'no_found_rows' => true, 'update_post_term_cache' => false, 'update_post_meta_cache' => false ) );

        if ( $my_query->have_posts() ) :

            while ( $my_query->have_posts() ) : $my_query->the_post();
                $postids[] = $post->ID;
            endwhile;

        endif;

        wp_reset_postdata();

    }

    print_r( $postids ); // printing the array.

?>

It's practically the same as running the 3 different loops but code is much cleaner now.