检查变量是否为空 [英] Check if a variable is empty

问题描述

我有一些用户提交的变量，希望在我的网站的其他部分显示，如下所示:

I have some user-submitted variables that I want to display in a different part of my site like this:

<div class="pre_box">Term: </div>
<div class="entry"><?php $key='term'; echo get_post_meta($post->ID, $key, true); ?></div>

有时，这些变量可能为空，在这种情况下，我不想显示空变量的标签.在上面的示例中，我想隐藏<div class="pre_box">Term: </div>部分.有什么简单的方法可以检查上面的php变量是否为空，并防止标签显示?

Occasionally, these variables might be empty in which case I don't want to display the label for the empty variable. In the example above I would want to hide the <div class="pre_box">Term: </div> part. Is there some simple way to check if a php variable like the one above is empty and prevent the label from being displayed?

更新，这是使用！empty

Update, here is the code using !empty

<?php $key='term' ?>
<?php if( !empty( $key ) ): ?> 
<div class="pre_box">Term: </div>
<div class="entry">
<?php echo get_post_meta($post->ID, $key, true); ?>
</div> 
<?php endif; ?>

但是，无论如何，它仍然显示内容.我认为问题可能出在我定义$ key变量的方式上.我试图从wordpress post中设置的自定义字段中提取数据，这就是$ post-> ID业务的全部内容.

However, this still displays the content no matter what. I think the problem might be in the way I am defining the $key variable. Im trying to pull data from a custom field set in a wordpress post - thats what the $post->ID business is all about.

推荐答案

<?php 
    $post_meta = get_post_meta($post->ID, 'term', true);
    if (!empty($post_meta)) {
?>
        <div class="pre_box">Term: </div>
        <div class="entry"><?php echo $post_meta; ?></div>
<?php
    }
?>

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