PHP infinitus classification uses reference to generate a tree

Welcome to the Linux community forum and interact with 2 million technical staff. First, check the code implementation functiongenerateTree ($ items) {$ treearray (); foreach ($ itemsas $ item) {if (isset ($ items [$ item [pid]) {$ items [$ item [pid] [son] [] $ items [$ item [id];

Welcome to the Linux community forum and interact with 2 million technical staff> first, check the code implementation function generateTree ($ items) {$ tree = array (); foreach ($ items as $ item) {if (isset ($ items [$ item ['pid ']) {$ items [$ item ['pid '] ['son'] [] = $ items [$ item ['id'];

Welcome to the Linux community forum and interact with 2 million technicians>

First, check the code implementation.

Function generateTree ($ items ){

$ Tree = array ();

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' => 'anhui province '),

2 => array ('id' => 2, 'pid '=> 0, 'name' => 'zhejiang province '),

3 => array ('id' => 3, 'pid '=> 1, 'name' => 'hefei '),

4 => array ('id' => 4, 'pid '=> 3, 'name' => 'changfeng County '),

5 => array ('id' => 5, 'pid '=> 1, 'name' => 'anqing '),

);

Print_r (generateTree ($ items ));

Output result

Array

(

[0] => Array

(

[Id] => 1

[Pid] => 0

[Name] => Anhui Province

[Son] => Array

(

[0] => Array

(

[Id] => 3

[Pid] => 1

[Name] => Hefei

[Son] => Array

(

[0] => Array

(

[Id] => 4

[Pid] => 3

[Name] => Changfeng County

)

)

)

[1] => Array

(

[Id] => 5

[Pid] => 1

[Name] => Anqing City

)

)

)

[1] => Array

(

[Id] => 2

[Pid] => 0

[Name] => Zhejiang Province

)

)

The code is concise and refined, without recursion, And the execution speed is fast. I accidentally saw this on a website and shared it with you if it was very practical.

The preceding tree generation method can also be reduced to five rows:

Function generateTree ($ items ){

Foreach ($ items as $ item)

$ Items [$ item ['pid '] ['son'] [$ item ['id'] = & $ items [$ item ['id'];

Return isset ($ items [0] ['son'])? $ Items [0] ['son']: array ();

}

The above method of tree structure of infinitus classified data is worth learning. But I don't think the actual use of this Code is obvious. You still need to recursively retrieve the formatted tree data:

/**

* How to retrieve formatted tree data

*/

$ Tree = generateTree ($ items );

Function getTreeData ($ tree ){

Foreach ($ tree as $ t ){

Echo $ t ['name'].'
';

If (isset ($ t ['son']) {

GetTreeData ($ t ['son']);

}

}

}

GetTreeData ($ tree );

I don't understand why does it need to be recursively retrieved. If I output the returned value of generateTree () as json to the front end, isn't it good?