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5行代码足矣，不用递归实现无限分类数据的树形格式化

2013-07-14 11:31 831 查看



[转]5行代码足矣，不用递归实现无限分类数据的树形格式化5月13日

我们知道很多开源软件的无限分类都是采用递归的算法，但是我们知道递归即浪费时间，又浪费空间（内存），

上次我也分享了个我自己原创的无限分类生成树的方法，一热心php高手网友给我提出了宝贵的建议，我测试了一下，这段代码的时间非常之短，参考：http://www.oschina.net/code/snippet_98719_11296，我再次整理了一下，发现数据库查询出数据之后，我们就已经定好了键值，因而实践中，我们一般会在model中查询出格式化成主键值对应数据的形式，因而我们可以直接用这样的数据，就少了一层循环。代码也非常简洁。
/**
*
此方法由@Tonton提供
'target='_blank'>http://my.oschina.net/u/918697[/code]
*
*
@date2012-12-12
*/
function
genTree5(
$items
)
{
foreach
(
$items
as
$item
)
$items
[
$item
[
'pid'
]][
'son'
][
$item
[
'id'
]]
=&
$items
[
$item
[
'id'
]];
return
isset(
$items
[0][
'son'
])
?
$items
[0][
'son'
]
:
array
();
}
/**
*
将数据格式化成树形结构
*
@authorXuefen.Tong
*
@paramarray$items
*
@returnarray
*/
function
genTree9(
$items
)
{
$tree
=
array
();
//格式化好的树
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'
=>
'江西省'
),
2
=>
array
(
'id'
=>
2,
'pid'
=>
0,
'name'
=>
'黑龙江省'
),
3
=>
array
(
'id'
=>
3,
'pid'
=>
1,
'name'
=>
'南昌市'
),
4
=>
array
(
'id'
=>
4,
'pid'
=>
2,
'name'
=>
'哈尔滨市'
),
5
=>
array
(
'id'
=>
5,
'pid'
=>
2,
'name'
=>
'鸡西市'
),
6
=>
array
(
'id'
=>
6,
'pid'
=>
4,
'name'
=>
'香坊区'
),
7
=>
array
(
'id'
=>
7,
'pid'
=>
4,
'name'
=>
'南岗区'
),
8
=>
array
(
'id'
=>
8,
'pid'
=>
6,
'name'
=>
'和兴路'
),
9
=>
array
(
'id'
=>
9,
'pid'
=>
7,
'name'
=>
'西大直街'
),
10
=>
array
(
'id'
=>
10,
'pid'
=>
8,
'name'
=>
'东北林业大学'
),
11
=>
array
(
'id'
=>
11,
'pid'
=>
9,
'name'
=>
'哈尔滨工业大学'
),
12
=>
array
(
'id'
=>
12,
'pid'
=>
8,
'name'
=>
'哈尔滨师范大学'
),
13
=>
array
(
'id'
=>
13,
'pid'
=>
1,
'name'
=>
'赣州市'
),
14
=>
array
(
'id'
=>
14,
'pid'
=>
13,
'name'
=>
'赣县'
),
15
=>
array
(
'id'
=>
15,
'pid'
=>
13,
'name'
=>
'于都县'
),
16
=>
array
(
'id'
=>
16,
'pid'
=>
14,
'name'
=>
'茅店镇'
),
17
=>
array
(
'id'
=>
17,
'pid'
=>
14,
'name'
=>
'大田乡'
),
18
=>
array
(
'id'
=>
18,
'pid'
=>
16,
'name'
=>
'义源村'
),
19
=>
array
(
'id'
=>
19,
'pid'
=>
16,
'name'
=>
'上坝村'
),
);
echo
"<pre>"
;
print_r(genTree5(
$items
));
print_r(genTree9(
$items
));
后者输出格式，前者类似，只是数组键值不一样，不过不影响数据结构

/*
Array
(
[0]
=>Array
(
[id]
=>1
[pid]
=>0
[name]
=>江西省
[son]
=>Array
(
[0]
=>Array
(
[id]
=>3
[pid]
=>1
[name]
=>南昌市
)
[1]
=>Array
(
[id]
=>13
[pid]
=>1
[name]
=>赣州市
[son]
=>Array
(
[0]
=>Array
(
[id]
=>14
[pid]
=>13
[name]
=>赣县
[son]
=>Array
(
[0]
=>Array
(
[id]
=>16
[pid]
=>14
[name]
=>茅店镇
[son]
=>Array
(
[0]
=>Array
(
[id]
=>18
[pid]
=>16
[name]
=>义源村
)
[1]
=>Array
(
[id]
=>19
[pid]
=>16
[name]
=>上坝村
)
)
)
[1]
=>Array
(
[id]
=>17
[pid]
=>14
[name]
=>大田乡
)
)
)
[1]
=>Array
(
[id]
=>15
[pid]
=>13
[name]
=>于都县
)
)
)
)
)
[1]
=>Array
(
[id]
=>2
[pid]
=>0
[name]
=>黑龙江省
[son]
=>Array
(
[0]
=>Array
(
[id]
=>4
[pid]
=>2
[name]
=>哈尔滨市
[son]
=>Array
(
[0]
=>Array
(
[id]
=>6
[pid]
=>4
[name]
=>香坊区
[son]
=>Array
(
[0]
=>Array
(
[id]
=>8
[pid]
=>6
[name]
=>和兴路
[son]
=>Array
(
[0]
=>Array
(
[id]
=>10
[pid]
=>8
[name]
=>
东北林业大学
)
[1]
=>Array
(
[id]
=>12
[pid]
=>8
[name]
=>
哈尔滨师范大学
)
)
)
)
)
[1]
=>Array
(
[id]
=>7
[pid]
=>4
[name]
=>南岗区
[son]
=>Array
(
[0]
=>Array
(
[id]
=>9
[pid]
=>7
[name]
=>西大直街
[son]
=>Array
(
[0]
=>Array
(
[id]
=>11
[pid]
=>9
[name]
=>
哈尔滨工业大学
)
)
)
)
)
)
)
[1]
=>Array
(
[id]
=>5
[pid]
=>2
[name]
=>鸡西市
)
)
)
)*/

                                            

                                        

                        
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