Hello at the moment I'm wondering how I would be able to make this work to post in Hierarchical order within the post loop.

<?php 
    foreach ((get_the_category()) as $childcat) 
    { 
        if (cat_is_ancestor_of('42', $childcat)) 
        { 
            echo '<li> <a href="'.get_category_link($childcat->cat_ID).'">'; echo $childcat->cat_name . '</a> </li>'; 
        }
    }
?>

I would like it to output as such:

• Parent
  • Child
  • Child
    • Grandchild

Hello at the moment I'm wondering how I would be able to make this work to post in Hierarchical order within the post loop.

<?php 
    foreach ((get_the_category()) as $childcat) 
    { 
        if (cat_is_ancestor_of('42', $childcat)) 
        { 
            echo '<li> <a href="'.get_category_link($childcat->cat_ID).'">'; echo $childcat->cat_name . '</a> </li>'; 
        }
    }
?>

I would like it to output as such:

• Parent
  • Child
  • Child
    • Grandchild

• posts
• loop
• hierarchical
• categories

Share Improve this question edited Aug 5, 2012 at 15:16 Amit Kosti 3,61011 gold badge2222 silver badges3434 bronze badges asked Jun 22, 2012 at 18:54 espnicholasespnicholas 17944 silver badges1111 bronze badges

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3 Answers 3

Sorted by: Reset to default 2

Use wp_list_categories instead,

<?php 

    $args = array(
    'hierarchical'       => true,
    'child_of'            => 42,   //parent category
    'hide_empty'         => 1,    //hide empty categories (set to 0 to show)
    );

    wp_list_categories($args); 

?> 

A full list of parameters for wp_list_categories can be found HERE

As you can see its highly customizable simply by adding extra arguements to the array stored in the $args variable that we later pass to the wp_list_categories function.

Note: Adding the child_of => ID argument you can specify the parent ID of the category for which you want to retrieve category terms for. Be aware that if there are no posts in the parent category, it will not show, in which case you may try setting hide_empty => 0 instead.

UPDATE

Well, instead of writing this from scratch myself, Scribu already has thankfully, so please take a look at the following link for more details;

http://scribu/wordpress/extending-the-category-walker.html

You need to sort the categories to make sure they come in the correct order:

// get categories of post in sorted order
$categories = sortCategories(get_the_category());     

function sortCategories($categories) { // Sorting the category
    usort($categories, "cmpCategories");
    return $categories;
}

function cmpCategories($category_1,$category_2) { // Sort function
    foreach(get_categories(array("parent" => $category_1->cat_ID)) AS $sub) {
        if($category_2->cat_ID == $sub->cat_ID) return -1;
    }
    return 1;
}

In addition to @tobidude's great solution, a complete exemple:

Create the functions

function sortCategories($categories) { // Sorting the category
    usort($categories, "cmpCategories");
    return $categories;
}

function cmpCategories($category_1,$category_2) { // Sort function
    foreach(get_categories(array("parent" => $category_1->cat_ID)) AS $sub) {
        if($category_2->cat_ID == $sub->cat_ID) return -1;
    }
    return 1;
}

Call your WP_Query... and during the loop call the get_the_category() inside the function sortCategories:

$sub_cat = sortCategories(get_the_category()); 

Before print the category, I created a conditional to get the deepest category:

if(isset($sub_cat[2])):
  echo $sub_cat[2]->name;
elseif(isset($sub_cat[1])):
  echo $sub_cat[1]->name;
else:
  echo $sub_cat[0]->name;
endif;