Group by common array keys - php

Question

$sortMod = [
[
'group_id' => 1,
'group_name'=>'Home',
'module_id' => 1,
'mod_name' => 'Home',
'mod_link' => '/home',
'var_name' => 'home'
], [
'group_id'=> 2,
'module_id' => 2,
'mod_name' => 'Numbers',
'mod_link' => '/number_mapping',
'var_name' => 'numbermap'
], [
'group_id'=> 2,
'module_id' => 70,
'mod_name' => 'DR Plan',
'mod_link' => '/dr_plan',
'var_name' => 'dr_plan'
], [
'group_id'=> 3,
'module_id' => 8,
'mod_name' => 'Reporting',
'mod_link' => '/reporting',
'var_name' => 'reporting'
], [
'group_id'=> 3,
'module_id' => 80,
'mod_name' => 'Scheduler',
'mod_link' => '/scheduler',
'var_name' => 'scheduler'
]
];
I want to group the result by group_id;
$sortMod = [
[
'group_id' => 1,
'group_name'=>'Home',
'module_id' => 1,
'mod_name' => 'Home',
'mod_link' => '/home',
'var_name' => 'home'
], [
'group_id'=> 2,
[
'module_id' => 2,
'mod_name' => 'Numbers',
'mod_link' => '/number_mapping',
'var_name' => 'numbermap'
], [
'module_id' => 70,
'mod_name' => 'DR Plan',
'mod_link' => '/dr_plan',
'var_name' => 'dr_plan'
]
], [
'group_id'=> 3,
[
'module_id' => 8,
'mod_name' => 'Reporting',
'mod_link' => '/reporting',
'var_name' => 'reporting'
], [
'module_id' => 80,
'mod_name' => 'Scheduler',
'mod_link' => '/scheduler',
'var_name' => 'scheduler'
]
]
];
Currently I have this:
$groups = [];
$modules = array();
I am iterating over the array $sortMod and group it by group_id where multiple module_id appears i.e group_id 2 and 3 has multiple modules in them. So the result will look what is stated above. Although I know I can have a flag variable $groupExist set to false by default and when the group is pushed into the $groups array, the value is set to false. Then have an if statement check if the value is true, then push just the module values :
foreach($sortMod as $val) {
if(!array_key_exists($val['group_id'],$groups)){
$groups[$val['group_id']] = [];
}
$groups[$val['group_id']][] = $val;
}
echo '<pre>';
print_r($groups);
echo '<pre>';

Answer 1

You can use array_reduce to group the array. If you don't want to make a multidimensional array if the group has only one element, you can use array_map
$sortMod = .. //Your array here.
$grouped = array_reduce($sortMod, function($c, $v){
$c[ $v['group_id'] ][] = $v;
return $c;
}, array());
$result = array_map(function ($n) {
if ( count($n) === 1 ) return $n[0]; //Since the group has one element. Return the element 0.
$newN = array(); //Contruct the new format for 2 or more elements.
$newN['group_id'] = $n[0]['group_id']; //Add the group_id
foreach($n as $value) //Loop thru the array, remove the group_id and push.
{
unset($value['group_id']);
$newN[] = $value;
}
return $newN;
}, $grouped );
echo "<pre>";
print_r( $result );
echo "</pre>";
This will result to:
Array
(
[1] => Array
(
[group_id] => 1
[group_name] => Home
[module_id] => 1
[mod_name] => Home
[mod_link] => /home
[var_name] => home
)
[2] => Array
(
[group_id] => 2
[0] => Array
(
[module_id] => 2
[mod_name] => Numbers
[mod_link] => /number_mapping
[var_name] => numbermap
)
[1] => Array
(
[module_id] => 70
[mod_name] => DR Plan
[mod_link] => /dr_plan
[var_name] => dr_plan
)
)
[3] => Array
(
[group_id] => 3
[0] => Array
(
[module_id] => 8
[mod_name] => Reporting
[mod_link] => /reporting
[var_name] => reporting
)
[1] => Array
(
[module_id] => 80
[mod_name] => Scheduler
[mod_link] => /scheduler
[var_name] => scheduler
)
)
)

Answer 2

Adding some little modifications to your code would make a something like that
$group = [];
foreach ($sortMod as $val){
$current_id = $val['group_id'];
unset($val['group_id']);
if (!array_key_exists($current_id ,$group)){
$group[$current_id] = array();
}
$group[$current_id][] = $val;
}
echo '<pre>';
print_r($groups);
echo '<pre>';

Answer 3

You could add your $val into the group using the group_id. If you find this key, you can create the group_id key. If you find it again, and it's an array, append to it.
$groups = [];
foreach($sortMod as $val)
{
$group_id = $val['group_id'];
if (!isset($groups[$group_id])) { // First case
$groups[$group_id] = $val ;
continue;
}
// regroup if 'group_id' is not an array
if (!is_array($groups[$group_id]['group_id']))
{
unset($groups[$group_id]['group_id']);
$groups[$group_id] = ['group_id' => $group_id, $groups[$group_id]] ;
}
// append the new group
unset($val['group_id']);
$groups[$group_id][] = $val ;
}
// optionnal (to remove group_id keys)
$groups = array_values($groups);
print_r($groups);
Outputs:
Array
(
[0] => Array
(
[group_id] => 1
[group_name] => Home
[module_id] => 1
[mod_name] => Home
[mod_link] => /home
[var_name] => home
)
[1] => Array
(
[group_id] => 2
[0] => Array
(
[module_id] => 2
[mod_name] => Numbers
[mod_link] => /number_mapping
[var_name] => numbermap
)
[1] => Array
(
[module_id] => 70
[mod_name] => DR Plan
[mod_link] => /dr_plan
[var_name] => dr_plan
)
)
[2] => Array
(
[group_id] => 3
[0] => Array
(
[module_id] => 8
[mod_name] => Reporting
[mod_link] => /reporting
[var_name] => reporting
)
[1] => Array
(
[module_id] => 80
[mod_name] => Scheduler
[mod_link] => /scheduler
[var_name] => scheduler
)
)
)

Answer 4

You could use a generic custom function like so:
function array_group_by($a, $i, $rem = true){
foreach($a as $v){
$k = $v[$i];
if($rem){
unset($v[$i]);
}
$t[$k][] = $v;
}
return $t;
}
echo '<pre>';
print_r(array_group_by($sortMod, 'group_id'));
echo '<pre>';
And here is the output.
A group id is supposed to be unique anyways, while this output is not what you specifically wanted it makes a more usable array to loop over.
The first key is the group_id. The following arrays that are in the group array contains are the "modules".
Optionally, you can use array_group_by($sortMod, 'group_id', false); to keep the group_id within that array.
Now when looping over it:
foreach(array_group_by($sortMod, 'group_id') as $groupid => $modules){
echo "$groupid is the group_id and contains " . count($modules) . " modules";
foreach($modules as $module){
echo "Hi from " . $module['module_id'];
}
}
In my opinion, short and reusable code is the way to go.