听过在文章内容前或者文章内容后添加代码！！如果想在 WordPress 文章段落后添加自定义内容，比如在文章第二段后添加广告，可以尝试用下面的代码：

// 在文章第二段之后插入内容
    add_filter( 'the_content', 'prefix_insert_post_ads' );
    function prefix_insert_post_ads( $content ) {
    	$ad_code = '<div>添加的文字</div>';
    	if ( is_single() && ! is_admin() ) {
    		return prefix_insert_after_paragraph( $ad_code, 2, $content );
    	}
    return $content;
    }
 
    // 主要函数
    function prefix_insert_after_paragraph( $insertion, $paragraph_id, $content ) {
    	$closing_p = '</p>';
    	$paragraphs = explode( $closing_p, $content );
    	foreach ($paragraphs as $index => $paragraph) {
    		if ( trim( $paragraph ) ) {
    			$paragraphs[$index] .= $closing_p;
    		}
    		if ( $paragraph_id == $index + 1 ) {
    			$paragraphs[$index] .= $insertion;
    		}
    	}
    	return implode( '', $paragraphs );
    }

分别在段落 2、4、6 后面添加不同的内容

add_filter( 'the_content', 'add_ads_to_content' );
    function add_ads_to_content( $content ) {
    	$ads = array(
    		2 =>  'ad code 1', // paragraph_id => ad_code
    		4 => 'ad code 2', // paragraph_id => ad_code
    		6 => 'ad code 3' // paragraph_id => ad_code
    	);
 
    	if ( is_single() && ! is_admin() ) {
    		foreach ($ads as $paragraph_id => $ad_code) {
    			$content = prefix_insert_after_paragraph( $ad_code, $paragraph_id, $content );
    		}
    	}
    	return $content;
    }
 
    function prefix_insert_after_paragraph( $insertion, $paragraph_id, $content ) {
    	$closing_p = '</p>';
    	$paragraphs = explode( $closing_p, $content );
    	foreach ($paragraphs as $index => $paragraph) {
    		if ( trim( $paragraph ) ) {
    			$paragraphs[$index] .= $closing_p;
    		}
    		if ( $paragraph_id == $index + 1 ) {
    			$paragraphs[$index] .= $insertion;
    		}
    	}
    	return implode( '', $paragraphs );
    }

如果只显示在某个分类文章中添加，也可以这么写

add_filter( 'the_content', 'prefix_insert_post_ads' );
    function prefix_insert_post_ads( $content ) {
    	$ad_code = '<div>自定义文字</div>';
    		if ( is_single() && ! is_admin() && in_category('29') ) {
    		return prefix_insert_after_paragraph( $ad_code, $content );
    	}
    	return $content;
    }
 
 
    function prefix_insert_after_paragraph( $insertion, $content ) {
    	$closing_p = '</p>';
    	$paragraphs = explode( $closing_p, $content );
    	$paragraph_id = round(count($paragraphs) / 2);
    	foreach ($paragraphs as $index => $paragraph) {
    		if ( trim( $paragraph ) ) {
    			$paragraphs[$index] .= $closing_p;
    		}
    		if ( $paragraph_id == $index + 1 ) {
    		$paragraphs[$index] .= $insertion;
    		}
    	}
    	return implode( '', $paragraphs );
    }