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HomeBackend DevelopmentPHP Tutorialphp获取数组元素值的函数总结

在php的内置函数中,获取数组元素值的函数主要有 reset next current prev end 这几个函数。

reset (PHP 3, PHP 4, PHP 5)

函数定义 mixed reset ( array &array )

作用:该函数将 array 的内部指针倒回到第一个单元并返回第一个数组单元的值,如果数组为空则返回 FALSE。

例如:

<p><?php</p>$array=array('step one','step two','step three','step four');<br />echo reset($array);

//输出:step one

next (PHP 3, PHP 4, PHP 5)

函数定义 mixed next ( array &array )

作用:返回数组内部指针指向的下一个单元的值,或当没有更多单元时返回 FALSE。

例如:

<p><?php</p>$array=array('step one','step two','www','scutephp.com','step four');<br />echo next($array);

//输出:step two

警告:如果数组包含空的单元,或者单元的值是 0 则本函数碰到这些单元也返回 FALSE。要正确遍历可能含有空单元或者单元值为 0 的数组,参见 each() 函数。

current (PHP 3, PHP 4, PHP 5)

函数定义 mixed current ( array &array )

作用:返回当前被内部指针指向的数组单元的值,并不移动指针。初始指向插入到数组中的第一个单元。如果内部指针指向超出了单元列表的末端,current() 返回 FALSE。

警告:如果数组包含有空的单元(0 或者 "",空字符串)则本函数在碰到这个单元时也返回 FALSE。这使得用 current() 不可能判断是否到了此数组列表的末端。要正确遍历可能含有空单元的数组,用 each() 函数。next() 和 current() 的行为类似,只有一点区别,在返回值之前将内部指针向前移动一位。这意味着它返回的是下一个数组单元的值并将数组指针向前移动了一位。如果移动指针的结果是超出了数组单元的末端,则 next() 返回 FALSE。

下面是相关函数的使用例子:

<p><?php</p>$transport = array('foot', 'www', 'car', 'scutephp','com');<br />$mode = current($transport); // $mode = 'foot';<br />$mode = next($transport); // $mode = 'www';<br />$mode = next($transport); // $mode = 'car';<br />$mode = prev($transport); // $mode = 'www';<br />$mode = end($transport); // $mode = 'com';<br />$mode = current($transport); // $mode = 'com';<br />$mode = reset($transport); // $mode = 'foot';


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