有条件地回显打开和关闭HTML标签

Question

A lot of times in PHP, it is necessary to conditionally echo opening and closing tags. For example, when getting a list of elements, you only want to include the <ul> ... </ul> if there are more than 0 elements ( <li> s) to display. The most obvious solution is like this:

<?php
    $count = getCount();
    if($count > 0) {
        echo "<ul>";
    }
    for($i = 0; $i < $count; $i++) {
         // echo our items
         echo "<li>" . getItem() ."</li>";
    }
    if($count > 0) {
        echo "</ul>";
    }
?>

But we have the same if( ... ) twice. Is there a better way to conditionally echo the <ul> tags ?

Answer 1

Here you go... one if :

<?php
    $count = getCount();
    if($count > 0) {
        echo "<ul>";
        for($i = 0; $i < $count; $i++) {
            // echo our items
            echo "<li>" . getItem() ."</li>";
        }
        echo "</ul>";
    }
?>

This also skips an unnecessary for loop, which you currently have in your code :)

Of course I jest a bit. Once you finally get past the point of wanting to write spaghetti code, then you can look into various templating engines.

Answer 2

输出HTML的更好方法是使用模板引擎，而不是直接通过PHP代码输出任何HTML。

Answer 3

You don't need two if statements. You can just do it all in one statement.

if($count > 0) {
    echo "<ul>";
    for($i = 0; $i < $count; $i++) {
     // echo our items
     echo "<li>" . getItem() ."</li>";
    }
    echo "</ul>";
}