Reset postdata to custom query in nested queries

Question

I have a main query, in which I set up a new custom query to retrieve posts (think about 'related posts' or something like that). Than in each of those posts, I'm setting an other custom query, load data from a single post, then I should find a way to reset postdata to the first custom query. How can I do that? I tried wp_reset_postdata(), but that resets to main query.

A simplified code would look thus:

while ( have_posts() ) : the_post();

    //Set up custom query
    $args = array(
        //Query args
    );
    $custom_query = new WP_Query( $args );

    //Custom query loop:
    while ( $custom_query->have_posts() ) : $custom_query->the_post();
        //Display some data,

        //then set up a custom query again
        $args = array(
            //Different query args
        );
        $custom_nested_query = new WP_Query( $args );

        //Nested custom query loop
        while ( $custom_nested_query->have_posts() ) : $custom_nested_query->the_post();
            //Do stuff, then reset to $custom_query since
            //I still need the post before $custom_query proceeds with the loop and loads the next one
        endwhile;

        //Display some more data from post queried by $custom_query before $nested_query was created
    endwhile;
endwhile;

Answer 1

You can save the $post in some temp variable and just set the $post back to the temp variable

global $post;
while ( have_posts() ) : the_post();

    //Set up custom query
    $args = array(
        //Query args
    );
    $custom_query = new WP_Query( $args );

    //Custom query loop:
    while ( $custom_query->have_posts() ) : $custom_query->the_post();
        // Save global post into temp variable
        $temp_post = $post;

        //Display some data,

        //then set up a custom query again
        $args = array(
            //Different query args
        );
        $custom_nested_query = new WP_Query( $args );

        //Nested custom query loop
        while ( $custom_nested_query->have_posts() ) : $custom_nested_query->the_post();
            //Do stuff, then reset to $custom_query since
            //I still need the post before $custom_query proceeds with the loop and loads the next one
        endwhile;

        // Set the global $post back to the first custom query
        $post = $temp_post;
        //Display some more data from post queried by $custom_query before $nested_query was created

    endwhile;
    wp_reset_postdata();
endwhile;

Or just use foreach($custom_nested_query->posts as $mypost).