PHP链接未显示

我正在尝试使文本“ Facebook”成为可单击的链接,但是由于某种原因,它将不会出现在前端.

代码段：

function friend_contact() {

$healthcard = get_field('healthcard');
$facebook = get_field('facebook');
$phone = get_field('phone');
$fax   = get_field('fax');
$email = get_field('email');

$post_info = '';

if (isset($healthcard['url'])) {
    $img = get_stylesheet_directory_uri() . "/images/mail-icon.png";
    $post_info .= '<a class="healthcard" href="'.$healthcard['url'].'"><img src="'.$img.'" /> Download Contact</a>';
}

if (isset($facebook['url']) && isset($healthcard['url']) {
    $post_info .= ' | ';
}   

if (isset($facebook['url'])) {
$post_info .= '<a href="'.$facebook['url'].'"><i class="fa fa-facebook" style="color:blue"></i> Facebook</a>';
}


$post_info .= '<ul class="friend-contact">';
$post_info .= "<li>$email</li>";
$post_info .= "<li>p: $phone</li>";
$post_info .= "<li>f: $fax</li>";
$post_info .= "</ul>";

var_dump($facebook);    
var_dump(get_field('facebook'));

genesis_markup( array(
    'html5' => sprintf( '<div class="entry-Meta">%s</div>', $post_info ),
    'xhtml' => sprintf( '<div class="post-info">%s</div>', $post_info ),
) );
}

转储结果：

string(21) "https://www.yahoo.com" string(21) "https://www.yahoo.com"

带有[‘url’]的备用代码：

if (isset($facebook) && isset($healthcard['url']) {
    $post_info .= ' | ';
}

if (isset($facebook)) {
    $post_info .= '<a class="facebook" a href="$facebook"><i class="fa fa-facebook"></i> Facebook</a>';
    }

我认为问题的根源在于代码位[‘url’]
先感谢您

解决方法:

您使用单引号将字符串回显,因此它不会处理该变量.看起来好像在双引号之间,但这是字符串的一部分.所以要么做到

$post_info .= '<a class="facebook" href="'.$facebook.'"><i class="fa fa-facebook"></i> Facebook</a>';

或反引号.

$post_info .= "<a class='facebook' href='$facebook'><i class='fa fa-facebook'></i> Facebook</a>";

编辑：关于什么更好的方法,是另一个讨论.只要您保持一致.