php 按子数组值对数组进行分组
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Group array by subarray values
提问by Anson Kao
Here's an interesting challenge. I have an array of subarrays in the following format:
这是一个有趣的挑战。我有以下格式的子数组数组：
array
(
a => array ( id = 20, name = chimpanzee )
b => array ( id = 40, name = meeting )
c => array ( id = 20, name = dynasty )
d => array ( id = 50, name = chocolate )
e => array ( id = 10, name = bananas )
f => array ( id = 50, name = fantasy )
g => array ( id = 50, name = football )
)
And I would like to group it into a new array based on the id field in each subarray.
我想根据每个子数组中的 id 字段将它分组到一个新数组中。
array
(
10 => array
(
e => array ( id = 10, name = bananas )
)
20 => array
(
a => array ( id = 20, name = chimpanzee )
c => array ( id = 20, name = dynasty )
)
40 => array
(
b => array ( id = 40, name = meeting )
)
50 => array
(
d => array ( id = 50, name = chocolate )
f => array ( id = 50, name = fantasy )
g => array ( id = 50, name = football )
)
)
Thanks!
谢谢！
回答by Tim Cooper
$arr = array();
foreach ($old_arr as $key => $item) {
$arr[$item['id']][$key] = $item;
}
ksort($arr, SORT_NUMERIC);
回答by amosrivera
foreach($array as $key => $value){
$newarray[$value['id']][$key] = $value;
}
var_dump($newarray);
piece of cake ;)
小菜一碟 ;）
回答by Herbert
The following code adapts @Tim Cooper’s code to mitigate Undefined index: iderrors in the event that one of the inner arrays doesn’t contain an id:
以下代码改编@Tim Cooper 的代码以Undefined index: id在内部数组之一不包含id的情况下减轻错误：
$arr = array();
foreach($old_arr as $key => $item)
{
if(array_key_exists('id', $item))
$arr[$item['id']][$key] = $item;
}
ksort($arr, SORT_NUMERIC);
However, it will drop inner arrays without an id.
但是，它会删除没有 id 的内部数组。
E.g.
例如
$old_arr = array(
'a' => array ( 'id' => 20, 'name' => 'chimpanzee' ),
'b' => array ( 'id' => 40, 'name' => 'meeting' ),
'c' => array ( 'id' => 20, 'name' => 'dynasty' ),
'd' => array ( 'id' => 50, 'name' => 'chocolate' ),
'e' => array ( 'id' => 10, 'name' => 'bananas' ),
'f' => array ( 'id' => 50, 'name' => 'fantasy' ),
'g' => array ( 'id' => 50, 'name' => 'football' ),
'h' => array ( 'name' => 'bob' )
);
will drop the 'h' array completely.
将完全删除 'h' 数组。
回答by Piotr Olaszewski
You can also use Arrays::gorupByform ouzo-goodies:
您还可以使用Arrays::gorupBy表单ouzo-goodies：
$groupBy = Arrays::groupBy($array, Functions::extract()->id);
print_r($groupBy);
And result:
结果：
Array
(
[20] => Array
(
[0] => Array
(
[id] => 20
[name] => chimpanzee
)
[1] => Array
(
[id] => 20
[name] => dynasty
)
)
[40] => Array
(
[0] => Array
(
[id] => 40
[name] => meeting
)
)
[50] => Array
(
[0] => Array
(
[id] => 50
[name] => chocolate
)
[1] => Array
(
[id] => 50
[name] => fantasy
)
[2] => Array
(
[id] => 50
[name] => football
)
)
[10] => Array
(
[0] => Array
(
[id] => 10
[name] => bananas
)
)
)
And here is docs for Arraysand Functions.
这是Arrays和Functions 的文档。
回答by Ilia Choly
<?php
$array = array(
'a' => array ( 'id' => 20, 'names' => 'chimpanzee' ),
'b' => array ( 'id' => 40, 'name' => 'meeting' ),
'c' => array ( 'id' => 20, 'name' => 'dynasty' ),
'd' => array ( 'id' => 50, 'name' => 'chocolate' ),
'e' => array ( 'id' => 10, 'name' => 'bananas' ),
'f' => array ( 'id' => 50, 'name' => 'fantasy' ),
'g' => array ( 'id' => 50, 'name' => 'football' )
);
$result = array();
foreach($array as $key => $value){
$id = $value['id'];
if(!isset($result[$id])) $result[$id] = array();
$result[$id] = array($key => $value);
}
var_dump($result);
?>
