您可以查看WordPress用于解析短代码的代码，了解如何做到这一点。有几个有用的核心函数可以简化事情。

// our callback function to check for the shortcode.
// this is where you\'d put code to set a flag for rendering the shortcode elsewhere
// the complete tag is in $tag[0], which can be passed to do_shortcode later
function wpd_check_shortcode( $tag ){
    if( \'content_block\' == $tag[2] ){
        // convert string of attributes to array of key=>val pairs
        $attributes = shortcode_parse_atts( $tag[3] );
        if( array_key_exists( \'position\', $attributes )
            && \'top\' == $attributes[\'position\'] ){
                // move shortcode to sidebar here
                // return empty to strip shortcode
                return \'\';
        }
    }
    // return any non-matching shortcodes
    return $tag[0];
}

// source text with shortcode
$text = \'lorem ipsum [content_block]\';

// this generates a regex pattern for all registered shortcodes
$pattern = get_shortcode_regex();

// process all shortcodes through our callback function
$text = preg_replace_callback( "/$pattern/s", \'wpd_check_shortcode\', $text );

// modified $text with shortcode removed
echo $text;

add_filter( \'the_content\', \'wpse168789_shortcode_checker\' );
function wpse168789_shortcode_checker( $content ) {
    // 1. Does the shortcode exist?
    if( has_shortcode( $content, \'content_block\' ) ) {
        // 2. Is it using position=\'top\'?
        $regex = \'/\\[content_block[^\\]]*position=[\\\'"]?top[\\\'"]?[^\\]]*\\]/\';
        if( preg_match( $regex, $content ) ) {
                // 3. Filter the shortcode out of the_content
                $content = preg_replace( $regex, \'\', $content );
            }
    }
    return $content;
}

至于在另一个位置显示短代码的内容--this question 可能会指引你。

参考文献has_shortcode()

preg_match()

preg_replace()