在 Swift 上自动创建 arraylist 对象

Posted 2023-02-24

【中文标题】在 Swift 上自动创建 arraylist 对象

【英文标题】：create arraylist objects automatically on Swift

【发布时间】：2020-03-23 16:49:50

【问题描述】：

我有一个列表，我想根据我想要获得的属性进行划分。 例如。如果有这个列表，我想使用一个主列表创建 3 个不同的列表。

  var companiesf = [
    Directory(directoryId: 1, fullname: "Jose Luis", company: "A"), 
    Directory(directoryId: 2, fullname: "Fernando", company: "A"), 
    Directory(directoryId: 3, fullname: "Maria", company: "B"), 
    Directory(directoryId: 4, fullname: "Rodrigo", company: "B"),
    Directory(directoryId: 5, fullname: "Miguel", company: "C")
  ]

最后，我想得到这个结果

 var listA = [
     Directory(directoryId: 1, fullname: "Jose Luis", company: "A"), 
     Directory(directoryId: 2, fullname: "Fernando", company: "A")
   ]


   var listB = [
    Directory(directoryId: 3, fullname: "Maria", company: "B"), 
    Directory(directoryId: 4, fullname: "Rodrigo", company: "B")
   ]


   var listC = [
    Directory(directoryId: 5, fullname: "Miguel", company: "C")
   ]

但我不知道如何自动创建数组对象

非常感谢！

【参考方案1】：

您可以通过创建分组字典来创建公司数组

let groupedByCompany = Dictionary(grouping: companiesf, by: $0.company)

然后从中创建你的数组

let listA = grouped["A", default: []]
let listB = grouped["B", default: []]
let listC = grouped["C", default: []]

另一种选择是使用filter

let listA = companiesf.filter $0.company == "A"
let listB = companiesf.filter $0.company == "B"
let listC = companiesf.filter $0.company == "C" 

【讨论】：

谢谢。你知道如何在 Foreach 中阅读“groupedByCompany”吗？

你的意思是像this question