Different number of posts in each category

Question

I have categories driven site. I have different template for each category. I would like to set different number of posts – different for each category. Plus I would like to add proper previous and next links in each category.

for example in this category-1.php I want 4 posts per page:

<?php query_posts('showposts=4'); ?>
<a href="<?=next_posts()?>"> PREVIOUS </a>
<a href="<?=previous_posts()?>"> NEXT </a>
<?php if (have_posts()) : while (have_posts()) : the_post(); ?>
...
<?php endwhile; endif; ?>

but in this example next_posts() and previous_posts() doesn't work.

Answer 1

As @StephenHarris pointed out there's also the pre_get_posts filter.

function hwl_home_pagesize( $query ) 
{
    if ( is_category( 9 ) ) 
    {
        // If you want "posts per page"
        $query->query_vars['posts_per_page'] = 1;
        return;
    }
    if ( is_category( 'movie' ) )
    {
        // If you want "showposts"
        $query->query_vars['showposts'] = 50;
        return;
    }
}
add_action( 'pre_get_posts', 'hwl_home_pagesize', 1 );

^{Example altered from Codex example.}

Answer 2

You can use the pre_get_posts hook (conditionals are available):

function wpse47875_change_posts_per_page( $query ) {
    //Only alter main query. This only works for 3.3+
    if( ! $query->is_main_query() )
        return;

    if ( is_category('9') ){
        //Display 4 posts for category 1
        $query->set( 'posts_per_page', 4);
    }
}
add_action('pre_get_posts', 'wpse47875_change_posts_per_page', 1);

You probably only want to change the 'main query', so the first check is important. If you are using WP < 3.3 then you can check instead:

 if( $wp_the_query === $query ){
    //$query is the main query
 }else{
    //$query is *not* the main query
 }

Answer 3

Parse Request Action

Not shure if this will work - it may be that the conditionals are not working at this point...

// inside functions.php
function wpse47861_intercept_main_query( $wp )
{
    // default
    $nr_posts = 10; 

    if ( is_category( 'CAT NAME' ) )
        $nr_posts = 4;

    if ( is_category( array( 9 /*Ex. Cat-ID*/, 'CAT NAME A', 'CAT NAME B' ) ) )
        $nr_posts = 6;

    // Modify the main query object
    $wp->query_vars['showposts'] = $nr_posts;

    return $wp;
}
add_filter( 'parse_request', 'wpse47861_intercept_main_query' );

Posts Limit filter

This would be the other chance, as maybe conditionals are already available there.

function wpse47861_intercept_query_limit( $limit )
{
    // default
    $nr_posts = 10; 

    if ( is_category( 'CAT NAME' ) )
        $nr_posts = 4;

    if ( is_category( array( 9 /*Ex. Cat-ID*/, 'CAT NAME A', 'CAT NAME B' ) ) )
        $nr_posts = 6;

    return "LIMIT 0, {$nr_posts}";
}
add_filter( 'posts_limit', 'wpse47861_intercept_query_limit', 9999 );

Note: Both functions are not tested. Plus: Use on or the other. Both should be placed in your functions.php file.

Answer 4

With query_posts, pagination won't work correctly, unless you use query_posts() in a page template and you set the 'paged' query var appropriately: http://codex.wordpress.org/Template_Tags/query_posts

But it may be easier to use a plugin called Custom Post Limits and leave your category page loops the same. You can set different first page and paged limits for each category. See WordPress › Custom Post Limits « WordPress Plugins