百科狗reset() - 将数组的内部指针指向第一个单元 - php 数组函数
reset()
(PHP 4, PHP 5, PHP 7)
将数组的内部指针指向第一个单元
说明
reset(array &$array): mixedreset()将$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。
参数
$array输入的数组。
返回值
返回数组第一个单元的值，如果数组为空则返回FALSE。
范例
Example #1reset()例子
参见
current()返回数组中的当前单元each()返回数组中当前的键／值对并将数组指针向前移动一步end()将数组的内部指针指向最后一个单元next()将数组中的内部指针向前移动一位prev()将数组的内部指针倒回一位
GOTCHA: If your first element is false, you don't know whether it was empty or not. So don't count on a false return being an empty array.
As for taking first key of an array, it's much more efficient to RESET and then KEY, rather then RESET result of ARRAY_KEYS (as sugested by gardnerjohng at gmail dot com). This will give the same result but is much much faster. Larger arrays, better performance. Tested on 100-elements long array with 16 times faster results.
When used on a scalar or unset value, reset() spews warning messages. This is often a problem when accessing arrays generated from HTML form input data: these are scalar or unset if the user didn't enter sufficient information. You can silence these error messages by prefixing an @ (at sign) to reset(), but it is better style to protect your reset() and the following array traversal with an if (isset()). Example code:
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