PHP如何对树子元素进行降序排序';帕拉姆
我有一棵像这样的树PHP如何对树子元素进行降序排序';帕拉姆,php,sorting,tree,Php,Sorting,Tree,我有一棵像这样的树 array( array('name'=>'n1', 'timestamp'=>1000, 'children'=> array()), array('name'=>'n2', 'timestamp'=>2000, 'children'=> array( array('name'=>'n3', 'timestamp'=>3000, 'children'=> array()), array('name'=&g
array(
array('name'=>'n1', 'timestamp'=>1000, 'children'=> array()),
array('name'=>'n2', 'timestamp'=>2000, 'children'=> array(
array('name'=>'n3', 'timestamp'=>3000, 'children'=> array()),
array('name'=>'n4', 'timestamp'=>4000, 'children'=> array(
array('name'=>'n5', 'timestamp'=>4000, 'children'=> array()),
array('name'=>'n6', 'timestamp'=>3000, 'children'=> array())
)),
)),
array('name'=>'n7', 'timestamp'=>3000, 'children'=> array())
)
-n1
-n2
-n3
-n4
-n5
-n6
-n7
我想按每一级DESC上的时间戳对其进行排序,所以结果将是
-n7
-n2
-n4
-n5
-n6
-n3
-n1
函数时间戳\u排序(&$a和&$b)
{
如果(!empty($a['children']))
usort($a['children','timestamp_sort');
如果($a['timestamp']=$b['timestamp'])
返回0;
返回$a['timestamp']<$b['timestamp']?1:-1;
}
usort($tree,'timestamp_sort');
我假设您熟悉usort
函数-如果不熟悉,您应该阅读
除了基本用法之外,我们还做了两件事:
- 递归排序-当数组包含自身需要排序的项时,
函数调用自身timestamp\u sort
- 通过引用将参数传递给函数——这样,当我们对子数组进行排序时,我们的更改会更新原始数组。同样,如果你不熟悉推荐人,你应该
function timestamp_sort(&$a, &$b)
{
if (!empty($a['children']))
usort($a['children'], 'timestamp_sort');
if ($a['timestamp'] == $b['timestamp'])
return 0;
return $a['timestamp'] < $b['timestamp'] ? 1 : -1;
}
usort($tree, 'timestamp_sort');