Display Posts Shortcode - Exclude Categories

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<?php

/** 
 * Display Posts Shortcode - Exclude Categories
 * @author Bill Erickson
 * @link http://wordpress.org/extend/plugins/display-posts-shortcode/
 *
 * @param array $args
 * @param array $atts
 * @return array $args
 */
function be_display_posts_shortcode_exclude_categories( $args, $atts ) {
	if( isset( $atts['not_category'] ) ) {
		$cats = explode( ',', $atts['not_category'] );
		$args['category__not_in'] = $cats;
	}

	return $args;
}
add_filter( 'display_posts_shortcode_args', 'be_display_posts_shortcode_exclude_categories', 10, 2 );