现有数组：
[
0 => array:2 [
"week" => "30"
"nilai" => "230"
]
1 => array:2 [
"week" => "30"
"nilai" => "66"
]
2 => array:2 [
"week" => "29"
"nilai" => "72"
]
3 => array:2 [
"week" => "29"
"nilai" => "225"
]
4 => array:2 [
"week" => "28"
"nilai" => "213"
]
5 => array:2 [
"week" => "28"
"nilai" => "72"
]
]