Editing Loop So It Targets Specific Tags?

Question

Confused on how to achieve this, but what I'm trying to do is load posts with the tag "reviews" in the loop on the homepage.

Index.php:

<?php /* Start the Loop */ ?>
<?php while ( have_posts() ) : the_post(); ?>

    <?php
        get_template_part( 'content-reviews', get_post_format() );
    ?>


<?php endwhile; ?>


<?php else : ?>

<?php get_template_part( 'no-results', 'index' ); ?>

<?php endif; ?>

Answer 1

Use the pre_get_posts action to modify the main query. Place this in your functions.php file:

function wpa71787_home_tag_query( $query ) {
    if ( $query->is_home() && $query->is_main_query() ) {
        $query->set( 'tag', 'reviews' );
    }
}
add_action( 'pre_get_posts', 'wpa71787_home_tag_query' );

You can set any valid parameters of WP_Query with this method.

Edit, secondary query excluding tagged posts, use tag ID:

$query = new WP_Query( array( 'tag__not_in' => array( 42 ) ) );
while( $query->have_posts() ):
    $query->the_post();
    // loop stuff
endwhile;