Wordpress short code exclude by author - wordpress

Question

I have a shortcode in WordPress which shows the last post by author, the problem is that I want to exclude a concrete author(ID=13). The shortcode is the next:
function latest_posts_c( $array ) {
global $post;
$defaults = array(
'show' => 3,
'excerpt' => 'false',
'post_type' => 'post',
);
extract( shortcode_atts( $defaults, $array ) );
$args = array(
'posts_per_page' => $show,
'post_type' => $post_type,
);
// Gets posts form database
$query = new WP_Query( $args );
// Displays posts if available
if( $query ) {
$i = 0;
while ( $query->have_posts()) : $query->the_post();
if ($i == 0)
$html = '<div class="column dt-sc-one-third first">';
else
$html .= '<div class="column dt-sc-one-third">';
$html .= '<article id="post-'.get_the_ID().'" class="'.implode(' ', get_post_class('blog-entry')).'">';
$html .= '<div class="blog-entry-inner">';
$html .= '<div class="entry-meta">';
$html .= ' ';
$html .= ' <div class="date">';
$html .= ' <p>'.get_the_date('M').' '.get_the_date('d').' <span>'. get_the_date('Y') .'</span> </p>';
$html .= ' </div>';
$html .= '</div><!-- .entry-meta -->';
if( has_post_thumbnail() ):
$html .= '<div class="entry-thumb">';
$html .= ' '.get_the_post_thumbnail(get_the_ID(), 'medium').'';
$html .= '</div><!-- .entry-thumb -->';
endif;
$html .= '<div class="entry-details">';
if(is_sticky()):
$html .= ' <div class="featured-post"> <span class="fa fa-trophy"> </span> Destacado</div>';
endif;
$html .= ' <div class="entry-title">';
$html .= ' <h4>'.get_the_title().'</h4>';
$html .= ' </div>';
$html .= ' <div class="entry-metadata">';
$html .= ' <p class="author">';
$html .= '<span class="fa fa-user"> </span>';
$html .= ' '.get_the_author().'</p>';
$categories = 0;/*get_the_category();*/
$separator = ', ';
$output = '';
if($categories){
$j = 0;
foreach($categories as $category) {
$output .= ''.$category->cat_name.'';
$j++;
if ($j < count($categories)) $output .= $separator;
}
$html .= ' <p class="categories"><span class="fa fa-folder-open"> </span>'.$output.'</p>';
}
$html .= ' </div><!-- .entry-metadata-->';
$html .= ' <div class="entry-body">';
$html .= ' '.dttheme_excerpt(50);
$html .= ' <p><a href="'.get_permalink().'" title="'.get_the_title().'" class="dt-sc-button small read-more">';
$html .= ' Leer más <span class="fa fa-angle-double-right"> </span></a></p>';
$html .= ' </div>';
$html .= '</div><!-- .entry-details -->';
$html .= '</div><!-- .blog-entry-inner-->';
$html .= '</article>';
$html .= '</div>';
$i++;
endwhile;
}
$html .= '<div class="dt-sc-clear"></div>';
// Resets Post Data
wp_reset_postdata();
// Returns the results
return $html;
}
add_shortcode('latestposts_c', 'latest_posts_c');
I added an If to block the code if there is a post from author ID=13, but the problem is that the shortcode doesn't show anything. I'm also using "authors_in" to allow certain authors ID inside the array $args and $default but nothing....Any idea?

Answer 1

Try this:
$args = array(
'posts_per_page' => $show,
'post_type' => $post_type,
'author' => '-13'
);
The author parameter can be set to include/exclude specific authors.
Reference http://codex.wordpress.org/Class_Reference/WP_Query#Author_Parameters