Application of PHP closure features: replacing loops and improving code performance. _PHP Tutorial

<span $img</span> = <span $_FILES</span>['img'<span ];
</span><span if</span> (<span $img</span><span )
{
    </span><span //</span><span 文件存放目录，和本php文件同级</span>
    <span $dir</span> = <span dirname</span>(<span __file__</span><span );

    </span><span array_walk</span>(<span $img</span>['tmp_name'], <span function</span> (<span $value</span>) <span use</span>(<span $dir</span>,<span $img</span><span )
    {    </span><span //</span><span 保证$img['tmp_name']和$img['name']中索引的对应</span>
        <span $filename</span> = <span $img</span>['name'][<span array_search</span>(<span $value</span>, <span $img</span>['tmp_name'<span ])];
        </span><span //</span><span 设置上传路径</span>
         <span $savepath</span>="<span $dir</span>\\<span $filename</span>"<span ;
         </span><span //</span><span 上传，并返回状态</span>
        <span $state</span> = <span move_uploaded_file</span>(<span $value</span>, <span $savepath</span><span );
        </span><span //</span><span 如果上传成功，预览</span>
        <span if</span>(<span $state</span><span )
        {
               </span><span echo</span> "<img src='<span $filename</span>' alt='<span $filename</span>' /> "<span ;
        }
    });
}</span>