Post Loop Category first show parent then child

Question

Iam using this wp function to show category in my post

I have certain post where i put the same post in two categories

It is showing alphabetically, I want to show first parent then child category.

EDIT:

<?php the_category(', ') ?>

Answer 1

The following code will print out all the top-level categories first and then all the non-top-level categories, if that's what u wanted.

<?php 
$categories = get_the_category( get_the_ID() );
if( $categories ){
    $output = "";

    //display all the top-level categories first
    foreach ($categories as $category) {
        if( !$category->parent ){
            $output .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '" >' . $category->name.'</a>,';
        }
    }

    //now, display all the child categories
    foreach ($categories as $category) {
        if( $category->parent ){
            $output .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '" >' . $category->name.'</a>,';
        }
    }

    echo trim( $output, "," );
}
?>

So you can use the above code instead of the_category()