如何从数组中删除重复数据

Posted 2023-02-14

【中文标题】如何从数组中删除重复数据

【英文标题】：How to remove duplicates data from array

【发布时间】：2022-01-19 07:15:30

【问题描述】：

我正在我的应用中实现关注和关注功能。从 Firestone 获取数据并传递到函数数组数据后，我将数据存储在 firestore 上。

FirebaseReference(.Users).getDocuments(snapshot, error) in
    if error != nil 
        print("Document Error: ", error!)
     else 
        if let doc = snapshot, doc.isEmpty == false 
            print("User Document is present.")
            let desc = doc.documents
            for item in desc
            
                
                let user = item.data()
                let name = user["name"] as! String
                let uid = user["userID"] as! String
                let img = user["imgUrl"] as? String
                

                FirebaseReference(.Users).document(FUser.currentUser()?.userID ?? "").collection("Following").getDocuments(snapshot1,error) in
                    if error != nil 
                        print("Document Error: ", error!)
                     else 
                        if let doc1 = snapshot1, doc1.isEmpty == false 
                            let data = doc1.documents
                            
                            var followingid = ""
                            for newitem in data
                            
                                
                                let value = newitem.data()
                                followingid = value["followedToUserId"] as? String ?? ""
                                self.getPostData(name: name, uid: uid, img: img ?? "",followingId: followingid )
                            
                            
                        
                        else
                        
                            self.getPostData(name: name, uid: uid, img: img ?? "",followingId:"NA")
                        
                    
                
            
        
        else
        
            print("User Document is not present.")
        
    

如果我在这个函数中传递数据 self.getPostData() 在 for 循环中，我的数据会成倍增加。请任何人都可以帮助我解决这个问题。

谢谢

【问题讨论】：

是followingId相乘，其他(name,uid,,mage)不是还是所有数据都相乘？最好看看你的阵列给我们一个明确的答案

为什么不确保不添加重复项而不是删除重复项？

如果我在 for 循环之外编写函数，则在第二个中添加重复项，而不是添加重复项

@AnandVishwakarma 你的final data structure 应该是什么？可以添加getPostData的函数定义吗

那么问题出在getPostData函数上吗？

【参考方案1】：

使用集合

let a = ["hai","hai","hello"]
let unique = Array(Set(a))
print(unique)

output should -> ["hai", "hello"]

NB: result won't be in order, if you want remove a duplicate model , model just needs to confirm the class Hashable and the process and result would be same

struct User: Hashable
var name: String
var age: Int


let a = [User(name: "a",age:15), User(name: "a",age:15),User(name: "b",age:30)]
let unique = Array(Set(a))
print(unique)


result -> [main.User(name: "a", age: 15), main.User(name: "b", age: 30)]