_php instance of PHP two infinite classification methods

I. Recursive method

Copy Code code as follows:

$items = Array (
Array (' ID ' =>1, ' pid ' =>0, ' name ' => ' Level 11 '),
Array (' ID ' =>2, ' pid ' =>0, ' name ' => ' Level 12 '),
Array (' ID ' =>3, ' pid ' =>1, ' name ' => ' two level 21 '),
Array (' ID ' =>4, ' pid ' =>3, ' name ' => ' three level 31 '),
Array (' ID ' =>5, ' pid ' =>1, ' name ' => ' two level 22 '),
Array (' ID ' =>6, ' pid ' =>3, ' name ' => ' three level 32 '),
Array (' ID ' =>7, ' pid ' =>6, ' name ' => ' four level 41 '),
);
$i = 0;
function Formattree ($arr, $pid = 0) {
$tree = Array ();
$temp = Array ();
Global $i;
if ($arr) {
foreach ($arr as $k => $v) {
if ($v [' pid '] = = $pid) {//
$temp = Formattree ($arr, $v [' id ']);
$temp && $v [' son '] = $temp;
$tree [] = $v;
}
}
}
return $tree;
}
Print_r (Formattree ($items));

second, non-recursive method

Copy Code code as follows:

function Gentree ($items) {
$tree = Array (); Well-formatted tree
foreach ($items as $item)
if (Isset ($items [$item [' pid ']]) {
$items [$item [' pid ']][' son '] = & $items [$item [' id ']];
}
else{
$tree [] = & $items [$item [' id ']];
}
return $tree;
}

$items = Array (
1 => Array (' ID ' => 1, ' pid ' => 0, ' name ' => ' Level 11 '),
2 => Array (' ID ' => 2, ' pid ' => 1, ' name ' => ' two level 21 '),
3 => Array (' ID ' => 3, ' pid ' => 1, ' name ' => ' two level 23 '),
4 => Array (' ID ' => 4, ' pid ' => 9, ' name ' => ' three level 31 '),
5 => Array (' ID ' => 5, ' pid ' => 4, ' name ' => ' four level 43 '),
6 => Array (' ID ' => 6, ' PID ' => 9, ' name ' => ' three level 32 '),
7 => Array (' ID ' => 7, ' PID ' => 4, ' name ' => ' four level 41 '),
8 => Array (' ID ' => 8, ' PID ' => 4, ' name ' => ' four Level 42 '),
9 => Array (' ID ' => 9, ' pid ' => 1, ' name ' => ' two level 25 '),
=> Array (' ID ' =>, ' pid ' =>, ' name ' => ' two level 22 '),
One => array (' ID ' =>, ' pid ' => 0, ' name ' => ' Level 12 '),
=> Array (' ID ' =>, ' pid ' =>, ' name ' => ' two level 24 '),
=> Array (' ID ' =>, ' pid ' => 4, ' name ' => ' level four 44 '),
=> Array (' ID ' =>, ' pid ' => 1, ' name ' => ' Level two 26 '),
=> Array (' ID ' =>, ' pid ' => 8, ' name ' => ' level five ' 51 '),
=> Array (' ID ' =>, ' pid ' => 8, ' name ' => ' level five 52 '),
=> Array (' ID ' =>, ' pid ' => 8, ' name ' => ' level five 53 '),
=> Array (' ID ' =>, ' pid ' =>, ' name ' => ' six level 64 '),
);
Print_r (Gentree ($items));