The Loop

By the time a template loads, WordPress has already parsed the address and fetched the right posts from the database: a single article, a category list or search results. The template only has to print them. A construct simply called "the Loop" does that.

The Loop itself

<?php
// index.php
 
if (have_posts()) :
    while (have_posts()) :
        the_post();
        ?>
        <article>
            <h2><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
            <?php the_excerpt(); ?>
        </article>
        <?php
    endwhile;
else :
    ?>
    <p>No posts yet.</p>
    <?php
endif;

have_posts() checks whether posts remain. the_post() makes the next post the current one — after that the output functions know which post to work with.

Output functions

These functions work only inside the Loop.

the_ and get_the_

Functions with the the_ prefix print the value at once. Their get_the_ counterparts return it — for checks and your own transformations:

<?php
// content.php
 
$title = get_the_title();
?>
 
<h2 class="<?php echo strlen($title) > 60 ? 'title-long' : 'title'; ?>">
    <?php echo esc_html($title); ?>
</h2>
 
<time datetime="<?php echo esc_attr(get_the_date('c')); ?>">
    <?php echo esc_html(get_the_date('F j, Y')); ?>
</time>

Values obtained through get_ are escaped with esc_html() and esc_attr() before output.

The featured image

<?php
// content.php
 
if (has_post_thumbnail()) {
    the_post_thumbnail('large', ['class' => 'cover', 'loading' => 'lazy']);
}

WordPress creates the thumbnail, medium, large and full sizes when an image is uploaded. add_image_size('card', 600, 400, true) in functions.php adds your own size.

A single post

The template of a single article is built the same way — the Loop just has one post:

<?php
// single.php
 
get_header();
 
while (have_posts()) :
    the_post();
    ?>
    <article>
        <h1><?php the_title(); ?></h1>
        <div class="content"><?php the_content(); ?></div>
    </article>
    <?php
endwhile;
 
get_footer();

Pagination

How many posts go on a page is set under "Settings → Reading". One function prints the links to neighbouring pages:

<?php
// index.php
 
the_posts_pagination([
    'prev_text' => '← Back',
    'next_text' => 'Next →',
]);

Common mistake

Without the the_post() call the Loop becomes infinite: have_posts() always returns true because the current post never changes, and the page hangs. The while (have_posts()) and the_post() lines always go together.