场景
我们常日从db或者api中获取数组数据，然后进行处理，那如果数据太大怎么办？或者进行api要求的时候数据太大，如何分批进行，array_chunk登场了。
语法
array_chunk ( array $array , int $size [, bool $preserve_keys = FALSE ] ) : array$array 须要处理的数组$size 拆分后每个数组的元素数量$preserve_keys 是否须要担保key不变分割之后返回多维数组
利用
$userList = [ ['id' => 1, 'name' => '快乐的鸟', 'totalAmount' => 1000], ['id' => 2, 'name' => '愤怒的鸟', 'totalAmount' => 10], ['id' => 3, 'name' => '忧伤的鸟', 'totalAmount' => 100], ['id' => 4, 'name' => '勤奋的鸟', 'totalAmount' => 3000], ['id' => 5, 'name' => '孤单的鸟', 'totalAmount' => 9000],];// 两个元素进行分割print_r(array_chunk($userList, 2));/Array( [0] => Array ( [0] => Array ( [id] => 1 [name] => 快乐的鸟 [totalAmount] => 1000 ) [1] => Array ( [id] => 2 [name] => 愤怒的鸟 [totalAmount] => 10 ) ) [1] => Array ( [0] => Array ( [id] => 3 [name] => 忧伤的鸟 [totalAmount] => 100 ) [1] => Array ( [id] => 4 [name] => 勤奋的鸟 [totalAmount] => 3000 ) ) [2] => Array ( [0] => Array ( [id] => 5 [name] => 孤单的鸟 [totalAmount] => 9000 ) ))/
上面默认preserve_keys为false, 如果设置为true, 则新数组中的元素仍保持原数组中的索引index
print_r(array_chunk($userList, 2, true));/Array( [0] => Array ( [0] => Array ( [id] => 1 [name] => 快乐的鸟 [totalAmount] => 1000 ) [1] => Array ( [id] => 2 [name] => 愤怒的鸟 [totalAmount] => 10 ) ) [1] => Array ( [2] => Array ( [id] => 3 [name] => 忧伤的鸟 [totalAmount] => 100 ) [3] => Array ( [id] => 4 [name] => 勤奋的鸟 [totalAmount] => 3000 ) ) [2] => Array ( [4] => Array ( [id] => 5 [name] => 孤单的鸟 [totalAmount] => 9000 ) ))/
