(PHP 5 >= 5.2.0, PHP 7, PHP 8)
ArrayObject::asort — Sort the entries by value
$flags = SORT_REGULAR
) : boolSorts the entries in ascending order, such that its keys maintain their correlation with the values they are associated with.
This is used mainly when sorting associative arrays where the actual element order is significant.
Note:
如果两个成员完全相同，那么它们在排序数组中的相对顺序是未定义的。
flags
可选的第二个参数 flags
可以用以下值改变排序的行为：
排序类型标记：
SORT_REGULAR - 正常比较单元
详细描述参见 比较运算符 章节
SORT_NUMERIC - 单元被作为数字来比较
SORT_STRING - 单元被作为字符串来比较
SORT_LOCALE_STRING -
根据当前的区域（locale）设置来把单元当作字符串比较，可以用
setlocale() 来改变。
SORT_NATURAL - 和 natsort()
类似对每个单元以"自然的顺序"对字符串进行排序。
SORT_FLAG_CASE - 能够与
SORT_STRING 或
SORT_NATURAL
合并（OR 位运算），不区分大小写排序字符串。
Always returns true.
Example #1 ArrayObject::asort() example
<?php
$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
$fruitArrayObject = new ArrayObject($fruits);
$fruitArrayObject->asort();
foreach ($fruitArrayObject as $key => $val) {
echo "$key = $val\n";
}
?>
以上例程会输出：
c = apple b = banana d = lemon a = orange
The fruits have been sorted in alphabetical order, and the key associated with each entry has been maintained.