Collection

Peoples.php

<?php
function peoples(): Collection {
	$peoples = collect([
		[
			'sex' => 'masc',
			'age' => 19
		], [
			'sex' => 'fem',
			'age' => 4
		], [
			'sex' => 'masc',
			'age' => 5
		], [
			'sex' => 'fem',
			'age' => 13
		], [
			'sex' => 'fem',
			'age' => 7
		],
	]);

	return $peoples->groupBy([
		'sex',
		function (array $people) {
			return (string) $people['age'];
		}
	]);
}