PHP sort subgroup only of a multidimensional array - php

Question

not sure I'm missing something obvious, but I can't find in the other answers a way to sort a multidimensional array subgroups, without touching the main order.
I have an array like this
Array
(
[1] => Array
(
[name] => Apples
[type] => 1
[sales] => 10
)
[2] => Array
(
[name] => Apples
[type] => 2
[sales] => 30
)
[3] => Array
(
[name] => Apples
[type] => 3
[sales] => 20
)
[4] => Array
(
[name] => Oranges
[type] => 1
[sales] => 30
)
[5] => Array
(
[name] => Oranges
[type] => 2
[sales] => 10
)
[6] => Array
(
[name] => Oranges
[type] => 3
[sales] => 20
)
[7] => Array
(
[name] => Lemons
[type] => 1
[sales] => 10
)
[8] => Array
(
[name] => Lemons
[type] => 2
[sales] => 30
)
[9] => Array
(
[name] => Lemons
[type] => 3
[sales] => 20
)
)
What I need to do is sorting each 'name' group (Apples, Oranges and Lemons) by the key 'sales', leaving the order of keys 'name' Apples, Oranges and Lemons unaltered, so result should be like this:
Array
(
[1] => Array
(
[name] => Apples
[type] => 1
[sales] => 10
)
[2] => Array
(
[name] => Apples
[type] => 3
[sales] => 20
)
[3] => Array
(
[name] => Apples
[type] => 2
[sales] => 30
)
[4] => Array
(
[name] => Oranges
[type] => 2
[sales] => 10
)
[5] => Array
(
[name] => Oranges
[type] => 3
[sales] => 20
)
[6] => Array
(
[name] => Oranges
[type] => 1
[sales] => 30
)
[7] => Array
(
[name] => Lemons
[type] => 1
[sales] => 10
)
[8] => Array
(
[name] => Lemons
[type] => 3
[sales] => 20
)
[9] => Array
(
[name] => Lemons
[type] => 2
[sales] => 30
)
)
I can't find any way to do this, anyone can give me a hint about this?
Thanks!

Answer 1

#gege try this:
<?php
$arr = array(
array(
"name" => "Apples",
"type" => 1,
"sales" => 10
),
array(
"name" => "Apples",
"type" => 2,
"sales" => 30
),
array(
"name" => "Apples",
"type" => 3,
"sales" => 20
),
array(
"name" => "Oranges",
"type" => 1,
"sales" => 30
),
array(
"name" => "Oranges",
"type" => 2,
"sales" => 10
),
array(
"name" => "Oranges",
"type" => 3,
"sales" => 20
),
array(
"name" => "Lemons",
"type" => 1,
"sales" => 10
),
array(
"name" => "Lemons",
"type" => 2,
"sales" => 30
),
array(
"name" => "Lemons",
"type" => 3,
"sales" => 20
)
);
echo "<pre>";
print_r($arr); // array before
function sortArr($a, $b){
if($a["name"] == $b["name"]){
if($a["sales"] == $b["sales"]){
return 0;
}
return($a["sales"] < $b["sales"] ? -1 : 1);
}
else{
return($a["name"] < $b["name"] ? -1 : 1);
}
}
usort($arr, "sortArr");
echo "<pre>";
print_r($arr); // array after

Answer 2

For the sake of readability, I reduced your array (it should still work for yours though).
<?php
// The array structured as assumed according to your example
$groceries = array(
array(
"name" => "Apples",
"type" => 1,
"sales" => 10
),
array(
"name" => "Apples",
"type" => 2,
"sales" => 30
),
array(
"name" => "Apples",
"type" => 3,
"sales" => 20
),
);
/**
* See the PHP docs for more information: http://php.net/manual/en/function.usort.php
*/
$sortBySales = function ($a, $b){
return $a['sales'] - $b['sales'];
};
echo "<h1>Unsorted</h1>";
echo "<pre>";
var_dump($groceries);
echo "</pre>";
usort($groceries, $sortBySales);
echo "<h1>Sorted</h1>";
echo "<pre>";
var_dump($groceries);
echo "</pre>";
EDIT
I forgot that the array should have the names grouped as well. Now, #BunkerBoy alread posted the solution, but for the sake of completness, here is the updated sorting function:
$sortBySales = function ($a, $b){
if($a["name"] == $b["name"]){
return $a['sales'] - $b['sales'];
}else{
return($a["name"] < $b["name"] ? -1 : 1);
}
};
Note that the only difference to #BunkerBoy's function is that I reduced the comparison to a calculation.