php获取数组第一个值

如果数据默认key不使用数字，而是字符串时怎么获取第一值呢？下面给到一套获取数组的方法。根据实际情况决定用哪个吧。

<?php

$transport = array("foot", "bike", "car", "plane");
$mode = current($transport); // $mode = "foot";
$mode = next($transport);    // $mode = "bike";
$mode = current($transport); // $mode = "bike";
$mode = prev($transport);    // $mode = "foot";
$mode = end($transport);     // $mode = "plane";
$mode = current($transport); // $mode = "plane";
?>