How does php generate json? PHP method code to generate json

<?php
//json_encode(数组/对象)
$color = array(&#39;red&#39;,&#39;blue&#39;,&#39;green&#39;);
echo json_encode($color); //["red","blue","green"]
?>

<?php
$animal = array(&#39;east&#39;=>&#39;tiger&#39;,&#39;north&#39;=>&#39;wolf&#39;,&#39;south&#39;=>&#39;monkey&#39;);
echo json_encode($animal); //{"east":"tiger","north":"wolf","south":"monkey"}
?>

<?php
$file_arr = array();//保存文件名
$dir = dir("D:\\input");//目录
while($file = $dir->read()){//循环目录
    if($file !=".." && $file !="."){//判断不为返回上级
        $file_arr[] = $file;
    }
}echo json_encode($file_arr); //["1.png","2.png"]
?>