如何在 Swift iOS 中比较两个数组并从一个数组中删除匹配的元素

Question

I have two arrays.

let array1 = ["Lahari", "Vijayasri"];
let array2 = ["Lahari", "Vijayasri", "Ramya", "Keerthi"];

I want to remove the array1 elements in array2 and print the final array-like

result array = ["Ramya", "Keerthi"]

Answer 1

Converting the arrays to Set s and using subtract is a simple and efficient method:

let array1 = ["Lahari", "Vijayasri"]
let array2 = ["Lahari", "Vijayasri", "Ramya", "Keerthi"]

let resultArray = Array(Set(array2).subtracting(Set(array1)))

If maintaining the order of array2 is important then you can use filter with a set -

let compareSet = Set(array1)

let resultArray = array2.filter { !compareSet.contains($0) }

Answer 2

Paulw11 answer works perfectly. But if ordering in array is important you can do this:

let reuslt = array2.filter { !array1.contains($0) }

Answer 3

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

var array1 = ["Lahari", "Vijayasri"]
let array2 = ["Lahari", "Vijayasri", "Ramya", "Keerthi"]
let a = array2.difference(from: array1) // ["Ramya", "Keerthi"]

Answer 4

只收尾。

array2[array1.count...]