PHP foreach循环问题与第一个元素

Question

I'm trying to add first and last class to some LI elements and I'm having a problem with the first index. The code where I have the issue is here:

// this is always true, and all items get the `first` class
if ($i == 0) { $menu_item_class .= ' first'; } 

The entire code looks like this:

function social_icons( $menu_item_class='', $icon_class='', $title_class = ''){
   $menu_item_class .= ($title_class != '') ? ' no-title' : '';
   $social_network = array(
     0=>  array (
       "title"=> "ello",
       "url"=>"envato"
     ),
     1=> array (
       "title"=> "vk",
       "url"=> "envato"
     ),
     2=> array (
       "title"=> "twitter",
       "url"=> "envato"
     ),
     3=> array (
       "title"=> "lastfm",
       "url"=> "envato"
     )
   ); 
   $social_icon_wrapper = ' string';
   $type = ' string2';
   $count = 4;

   if ( $count > 0 ) { ?>
   <div id="social-network">
       <ul class="social-icons">
       <?php foreach ($social_network as $i=>$sn ){
           // var_dump($i); // this always returns fine
           if ( $i == 0 ) { $menu_item_class .= ' first'; } // for some reason this IF is always true
           if ( $i == ($count-1) ) { $menu_item_class .= ' last'; } ?>
           <?php if ( $sn['title'] == 'ello' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="ello" href="https://ello.co/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-ello"></i></span>ello</a></li><?php } ?>
           <?php if ( $sn['title'] == 'vk' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="vk" href="https://vk.com/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-vk"></i></span>vk</a></li><?php } ?>
           <?php if ( $sn['title'] == 'facebook' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="facebook" href="https://www.facebook.com/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-facebook"></i></span>facebook</a></li><?php } ?>
           <?php if ( $sn['title'] == 'pinterest' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="pinterest" href="https://pinterest.com/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-pinterest"></i></span>pinterest</a></li><?php } ?>
           <?php if ( $sn['title'] == 'twitter' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="twitter" href="https://www.twitter.com/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-twitter"></i></span>twitter</a></li><?php } ?>
           <?php if ( $sn['title'] == 'lastfm' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="lastfm" href="http://www.last.fm/user/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-lastfm"></i></span>lastfm</a></li><?php } ?>
       <?php } ?>      
       </ul>
   </div>

   <?php } 
 }
 social_icons();

I made a simple pen to illustrate the issue. Please check and let me know what's wrong.

Answer 1

Just so you can understand, take a lool at this code.

And more explanation: You have a variable $class_name that has, for example, the value abc, once it enters the foreach and the $i IS equals to 0, $class_name is going to be abc first. But from now on, you'll keep accessing $class_name, which is, guess what, abc first.

This Code is changed to keep the correct value (note that this might not be the best way, but what you need to understand is that once you add first to the variable, next time you access it, it's going to be there).

Take a look at the // ADDED THIS LINE lines:

function social_icons( $menu_item_class='', $icon_class='', $title_class = ''){
    $menu_item_class .= ($title_class != '') ? ' no-title' : '';
    $original_class = $menu_item_class; // ADDED THIS LINE
    $social_network = array(
      0=>  array (
        "title"=> "ello",
        "url"=>"envato"
      ),
      1=> array (
        "title"=> "vk",
        "url"=> "envato"
      ),
      2=> array (
        "title"=> "twitter",
        "url"=> "envato"
      ),
      3=> array (
        "title"=> "lastfm",
        "url"=> "envato"
      )
    ); 
    $social_icon_wrapper = ' string';
    $type = ' string2';
    $count = 4;

    if ( $count > 0 ) { ?>
    <div id="social-network">
        <ul class="social-icons">
        <?php foreach ($social_network as $i=>$sn ){
            // var_dump($i); // this always returns fine
            $menu_item_class = $original_class; // ADDED THIS LINE
            if ( $i == 0 ) { $menu_item_class .= ' first'; } // for some reason this IF is always true
            if ( $i == ($count-1) ) { $menu_item_class .= ' last'; }
            ?>
            <?php if ( $sn['title'] == 'ello' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="ello" href="https://ello.co/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-ello"></i></span>ello</a></li><?php } ?>
            <?php if ( $sn['title'] == 'vk' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="vk" href="https://vk.com/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-vk"></i></span>vk</a></li><?php } ?>
            <?php if ( $sn['title'] == 'facebook' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="facebook" href="https://www.facebook.com/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-facebook"></i></span>facebook</a></li><?php } ?>
            <?php if ( $sn['title'] == 'pinterest' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="pinterest" href="https://pinterest.com/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-pinterest"></i></span>pinterest</a></li><?php } ?>
            <?php if ( $sn['title'] == 'twitter' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="twitter" href="https://www.twitter.com/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-twitter"></i></span>twitter</a></li><?php } ?>
            <?php if ( $sn['title'] == 'lastfm' ) { ?> <li class="<?php echo $menu_item_class; ?>"><a class="lastfm" href="http://www.last.fm/user/<?php echo $sn['url']; ?>"><span class="social-icon-wrapper<?php echo $type; ?>"><i class="<?php echo $icon_class; ?> social-lastfm"></i></span>lastfm</a></li><?php } ?>
        <?php } ?>      
        </ul>
    </div>

    <?php } 
}
social_icons();