How to noindex automatically all post of a specific category? [closed]

by

Being excluded-cat and excluded-cat-1 the categories you want to exclude from indexing:

add_action('wp_head','AS_exclude_category_from_indexing');

function AS_exclude_category_from_indexing(){
  $html="";
  if(has_category('excluded-cat') || has_category('excluded-cat-1')){
    $html= "<meta name=\"robots\" content=\"noindex,follow\">".PHP_EOL;
  } 
  echo $html;
}