filter Wordpress Posts by Multiple category

Question

I am sorting post and displaying a single category with this code.

 global $post;
    $args = array( 
        'category_name'=>'oranges',
        'numberposts'   => -1,
    );

I would like to display all post that are in both "oranges" and "apple" categories so I have modified the code I am using to display a single category to this:

global $post;
    $args = array( 
        'category_name'=>'oranges',
        'category_name'=>'apples',
        'numberposts'   => -1,
    );

This displays only the post in the apples category.
Thanks

Answer 1

<ul>
    <?php
    global $post;

    $myposts = get_posts( array(
        'posts_per_page' => 5,
        'offset'         => 1,
        'category'       => 1 // category id here
    ) );

    if ( $myposts ) {
        foreach ( $myposts as $post ) : 
            setup_postdata( $post ); ?>
            <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
        <?php
        endforeach;
        wp_reset_postdata();
    }
    ?>
</ul>

Answer 2

Thanks Arsalan for the suggestion this code here is pulling only the posts in both categories.

global $post;
    $args = array( 
        'category_name'=>'oranges + apples',
        'numberposts'   => -1,
    );

Answer 3

Use (+) for multiple categories

global $post;
$args = array( 
    'category_name'=>'oranges + apples',
    'numberposts'   => -1,
);