PHP prev() 函数

2018-11-18 17:48 更新

PHP prev() 函数

实例

输出数组中的当前元素、下一个元素和上一个元素的值：

<?php
$people = array("Peter", "Joe", "Glenn", "Cleveland");

echo current($people) . " ";
echo next($people) . " ";
echo prev($people);
?>

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定义和用法

prev() 函数将内部指针指向数组中的上一个元素，并输出。

语法

prev(array)

参数	描述
array	必需。规定要使用的数组。

技术细节

返回值：	如果成功则返回数组中上一个元素的值，如果没有更多的数组元素则返回 FALSE。
PHP 版本：	4+

实例 1

所有相关方法的演示：

<?php
$people = array("Peter", "Joe", "Glenn", "Cleveland");

echo current($people) . " "; // The current element is Peter
echo next($people) . " "; // The next element of Peter is Joe
echo current($people) . " "; // Now the current element is Joe
echo prev($people) . " "; // The previous element of Joe is Peter
echo end($people) . " "; // The last element is Cleveland
echo prev($people) . " "; // The previous element of Cleveland is Glenn
echo current($people) . " "; // Now the current element is Glenn
echo reset($people) . " "; // Moves the internal pointer to the first element of the array, which is Peter
echo next($people) . " "; // The next element of Peter is Joe

print_r (each($people)); // Returns the key and value of the current element (now Joe), and moves the internal pointer forward
?>

运行实例 »