index loop 1post/cat

<?php

get_header(); ?>

<div id="primary">
<div id="content" role="main">

<?php
/* Set up an array to hold the ids for the categories we want to pull from
* The order in which the posts are called & displayed is goverened by their
* placement in this array
*/
$my_cat_array = array(6613,113,999,1123); //adjust ids to match your current site

/*
* Set up a flag that will indicate if we've returned ANY posts from any of the chosen categories
* As we don't have access to the standard Loop 404, we'll need this in case we
* bomb out on all categories. This kind of post counter can come in useful elsewhere...
*/
$posts_count = 0;

/*
* Rather than modify the main Loop, we'll use get_posts to create 3 secondary loops that grab * the first post from each of these categories. This has the benefit of leaving the main Loop * untouched if you want to call it later on in the page.
*/
$cat_posts = array(); //an array to collect the post ids of the one post per category//

foreach ( $my_cat_array as $my_cat) :

// Set up the secondary loop query
$args = array(
	'numberposts' => 1, // number of posts to return
	'category__in' => array($my_cat), // the category id
	'post__not_in' => $cat_posts // avoid duplicates
);
$lastpost = get_posts($args);

// If we have at least 1 post, increment the post_counts flag
if( count( $lastpost ) > 0 ) $posts_count++;

// We still have to run a foreach Loop - even if there's only 1 post.
foreach($lastpost as $post) :
$cat_posts[] = $post->ID; //'remember' the post ID
endforeach;
// Move onto the next post in the category array

endforeach;
// We've finished the category array!

// build a secondary loop with the post IDs from the category posts

$args = array(
'post__in' => $cat_posts,
'orderby' => 'date',
'order' => 'DESC',
'ignore_sticky_posts' => 1
 );
$cat_loop = new WP_Query( $args );

if( $cat_posts && $cat_loop->have_posts() ) : while( $cat_loop->have_posts() ) : $cat_loop->the_post();
// Now we can display the post using all of the standard Loop tags
?>
<div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
<h2 class="entry-title"><a href="<?php the_permalink(); ?>" title="<?php printf( esc_attr__( 'Permalink to %s', 'twentyeleven' ), the_title_attribute( 'echo=0' ) ); ?>" rel="bookmark"><?php the_title(); ?></a></h2>

<div class="entry-content">
<?php the_content( __( 'Continue reading <span class="meta-nav">&rarr;</span>', 'twentyeleven' ) ); ?>
<?php wp_link_pages( array( 'before' => '<div class="page-link">' . __( 'Pages:', 'twentyeleven' ), 'after' => '</div>' ) ); ?>
</div><!-- .entry-content -->

<div class="entry-utility">
<?php if ( count( get_the_category() ) ) : ?>
<span class="cat-links">
<?php printf( __( '<span class="%1$s">Posted in</span> %2$s', 'twentyeleven' ), 'entry-utility-prep entry-utility-prep-cat-links', get_the_category_list( ', ' ) ); ?>
</span>
<span class="meta-sep">|</span>
<?php endif; ?>
<?php
$tags_list = get_the_tag_list( '', ', ' );
if ( $tags_list ):
?>
<span class="tag-links">
<?php printf( __( '<span class="%1$s">Tagged</span> %2$s', 'twentyeleven' ), 'entry-utility-prep entry-utility-prep-tag-links', $tags_list ); ?>
</span>
<span class="meta-sep">|</span>
<?php endif; ?>
<span class="comments-link"><?php comments_popup_link( __( 'Leave a comment', 'twentyeleven' ), __( '1 Comment', 'twentyeleven' ), __( '% Comments', 'twentyeleven' ) ); ?></span>
<?php edit_post_link( __( 'Edit', 'twentyeleven' ), '<span class="meta-sep">|</span> <span class="edit-link">', '</span>' ); ?>
</div><!-- .entry-utility -->
</div><!-- #post-## -->

<?php endwhile; wp_reset_postdata();

// We now need to check that we did manage to display at least 1 post

else :
// Uh oh - we didn't display any posts! ?>
<div id="post-0" class="post error404 not-found">
<h1 class="entry-title"><?php _e( 'Not Found', 'twentyeleven' ); ?></h1>
<div class="entry-content">
<p><?php _e( 'Apologies, but no results were found for the requested archive. Perhaps searching will help find a related post.', 'twentyeleven' ); ?></p>
<?php get_search_form(); ?>
</div><!-- .entry-content -->
</div><!-- #post-0 -->
<?php endif;?>

</div><!-- #content -->
</div><!-- #primary -->

<?php get_sidebar(); ?>
<?php get_footer();