Answers for "how to get wordpress posts by category name"

get_posts category

$defaults_param = array(
				'numberposts'      	=> -1,
				'post_type'        	=> 'post',
				'category' 			=> 40 ,
				'suppress_filters'	=> false
			);
$get_featured_post = get_posts($defaults_param);

wordpress single post get category name

$category = get_the_category();
$firstCategory = $category[0]->cat_name;