I have a two dimensional array of students from different schools and countries. I want them to be grouped by name of school and country.
How can I create the nested key structure?
Example:
$students = [
[
"country" => "japan",
"school" => "kyoto university",
"name" => "Naruto Uzumaki"
],
[
"country" => "usa",
"school" => "harvard university",
"name" => "Naruto Uzumaki"
],
[
"country" => "japan",
"school" => "tokyo university",
"name" => "sasuke Uchiha"
],
[
"country" => "japan",
"school" => "tokyo university",
"name" => "kakashi hatake"
],
];
Desired result:
[
“japan” => [
“kyoto university” => [
[
“country” => “japan”,
“school” => “kyoto university”,
“name” => “Naruto Uzumaki”
],
],
“tokyo university” => [
[
“country” => “japan”,
“school” => “tokyo university”,
“name” => “sasuke Uchiha”
],
[
“country” => “japan”,
“school” => “tokyo university”,
“name” => “kakashi hatake”
],
],
],
“usa” => [
“harvard university” => [
[
“country” => “usa”,
“school” => “harvard university”,
“name” => “Naruto Uzumaki”
],
]
]
]
Pretty much creating an object or using an existing one. First create country object if not exists, then create school object under it (if not exists) then push to it.
$result = [];
foreach ($students as $student) {
$country = $student['country'];
$school = $student['school'];
$result[$country] = isset($result[$country]) ? $result[$country] : [];
$result[$country][$school] = isset($result[$country][$school]) ? $result[$country][$school] : [];
$result[$country][$school][] = $student;
}
print_r($result);
Output:
Array
(
[japan] => Array
(
[kyoto university] => Array
(
[0] => Array
(
[country] => japan
[school] => kyoto university
[name] => Naruto Uzumaki
)
)
[tokyo university] => Array
(
[0] => Array
(
[country] => japan
[school] => tokyo university
[name] => sasuke Uchiha
)
[1] => Array
(
[country] => japan
[school] => tokyo university
[name] => kakashi hatake
)
)
)
[usa] => Array
(
[harvard university] => Array
(
[0] => Array
(
[country] => usa
[school] => harvard university
[name] => Naruto Uzumaki
)
)
)
)