Sort PHP array by group of 3 keys [duplicate] - php

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Closed 11 years ago.
Possible Duplicate:
Sort multidimensional array by multiple keys
I am trying to find some way how to sort array by key name, but nothing worked so far. The tricky part for me is to sort array by grouping 3 keys. I have this array.
[0] => Array
(
[id] => 8
[zbo_data] => blah
)
[1] => Array
(
[id] => 6
[szn_data] => blah
)
[2] => Array
(
[id] => 5
[gcz_data] => blah
)
[3] => Array
(
[id] => 3
[gcz_data] => blah
)
[4] => Array
(
[id] => 2
[zbo_data] => blah
)
[5] => Array
(
[id] => 1
[szn_data] => blah
)
And I need to sort it by group of 3 in this order: szn_data, zbo_data, gcz_data but I also need to keep the order of [id] (basically primary order by szn_data, zbo_data, gcz_data, secondary [id]). Is there a solution? Or should I construct array differently to be able to sort it? I am trying to figure this out for over 6 hours. Any help is much appreciated.
My desired output is:
[0] => Array
(
[id] => 6
[szn_data] => blah
)
[1] => Array
(
[id] => 8
[zbo_data] => blah
)
[2] => Array
(
[id] => 5
[gcz_data] => blah
)
[3] => Array
(
[id] => 1
[szn_data] => blah
)
[4] => Array
(
[id] => 2
[zbo_data] => blah
)
[5] => Array
(
[id] => 3
[gcz_data] => blah
)

Answer 1

Use usort and implement your comparison function as you wish. For example:
$result = usort($arr, function($a,$b) {
$keys = array('szn_data', 'zbo_data', 'gcz_data');
foreach ($keys as $key) {
// make sure to add here handling of missing keys
$diff = strcmp($b[$key], $a[$key]);
if ($diff!=0) {
return $diff;
}
}
return $b['id'] - $a['id'];
});

Answer 2

Or like this, for any order from max to the min listed in one array
$arr = array (
array(
'id' => 8,
'zbo_data' => 'blah'
),
array(
'id' => 6,
'szn_data' => 'blah'
),
array(
'id' => 5,
'gcz_data' => 'blah'
),
array(
'id' => 3,
'gcz_data' => 'blah'
),
array(
'id' => 2,
'zbo_data' => 'blah'
),
array(
'id' => 1,
'szn_data' => 'blah'
)
);
usort($arr, "my_func");
var_dump($arr);
function my_func($a, $b)
{
$vars = array('szn_data', 'zbo_data', 'gcz_data'); // order of the keys
$id1 = $a['id']; $id2 = $b['id']; unset($a['id'], $b['id']);
$index1 = array_search(key($a), $vars);
$index2 = array_search(key($b), $vars);
if ($index1 == $index2) {
if ($id1 == $id2) return 0;
return ($id1 < $id2) ? 1 : -1;
}
return ($index1 < $index2) ? -1 : 1;
}
ps:
basically primary order by szn_data, zbo_data, gcz_data, secondary
[id]
It does not correspond to your desired output. Secondary means comparison of id when other keys are the same.
ps: Updated - this code is NOT nice or perfect, but it will give you what you need
$vars = array('szn_data', 'zbo_data', 'gcz_data');
$arr = array (
array(
'id' => 8,
'zbo_data' => 'blah'
),
array(
'id' => 6,
'szn_data' => 'blah'
),
array(
'id' => 5,
'gcz_data' => 'blah'
),
array(
'id' => 3,
'gcz_data' => 'blah'
),
array(
'id' => 2,
'zbo_data' => 'blah'
),
array(
'id' => 1,
'szn_data' => 'blah'
)
);
$temp = array();
$cnt = count($arr);
foreach($arr as $item)
{
foreach($vars as $v)
{
if (isset($item[$v])) { $temp[$v][$item['id']] = $item; break; }
}
}
// sort by id
foreach($vars as $v)
{
krsort($temp[$v]);
$temp[$v] = array_values($temp[$v]);
}
$arr = array(); $i = 0; $j = 0;
$completed = false;
do {
foreach($vars as $v)
{
if ($i++>=$cnt) { $completed = true; break; }
if (isset($temp[$v][$j])) $arr[] = $temp[$v][$j];
}
$j++;
} while (!$completed);
// output
var_dump($arr)