Swift Array 合集

数组去交集

How to find the difference between two arrays

extension Array where Element: Hashable {
    func difference(from other: [Element]) -> [Element] {
        let thisSet = Set(self)
        let otherSet = Set(other)
        return Array(thisSet.symmetricDifference(otherSet))
    }
}

使用：

let names1 = ["John", "Paul", "Ringo"]
let names2 = ["Ringo", "Paul", "George"]
let difference = names1.difference(from: names2)

数组去重

Swift之数组去重(去除重复元素)

如果数组内只含有基础类型的数据时，可以写两个for循环遍历，用下标取值做对比；当然也可以用集合 Set（Swift），比较方便快捷。

但是如果需要对 model 数组进行去重，则用不了 Set。

import UIKit

extension Array {
    
    // 去重
    func filterDuplicates<E: Equatable>(_ filter: (Element) -> E) -> [Element] {
        var result = [Element]()
        for value in self {
            let key = filter(value)
            if !result.map({filter($0)}).contains(key) {
                result.append(value)
            }
        }
        return result
    }
}

// 基础类型去重
let arrays = ["1", "2", "2", "3", "4", "4"]
let filterArrays = arrays.filterDuplicates({$0})
print(filterArrays)

// model类的去重
let modelArrays = [Model("1"), Model("1"), Model("2"), Model("3")]
let filterModels = modelArrays.filterDuplicates({$0.name})
print(filterModels)

Swift数组去重

let arr = ["apple", "strawberry", "pear", "apple", "orange", "orange", "strawberry"]
let results = arr.enumerated().filter { (index,value) -> Bool in
		return arr.firstIndex(of: value) == index
}.map {
    $0.element
}

or

 let arr = ["apple", "strawberry", "pear", "apple", "orange", "orange", "strawberry"]
 arr.removeDuplicate()
 // Array 扩展
 public extension Array where Element: Equatable {
    
    /// 去除数组重复元素
    /// - Returns: 去除数组重复元素后的数组
    func removeDuplicate() -> Array {
       return self.enumerated().filter { (index,value) -> Bool in
            return self.firstIndex(of: value) == index
        }.map { (_, value) in
            value
        }
    }
}

Set 操作

wift5 集合（Set）操作