iOS swift从另一个数组中删除数组的元素

Question

我有两个数组

var array1 = new Array ["a", "b", "c", "d", "e"]
var array2 = new Array ["a", "c", "d"]

我想从array1中删除array2的元素

Result ["b", "e"]

Answer 1

@ 安东尼奥的解决方案是更好的性能,但这种保留排序,如果这是很重要的:

var array1 = ["a", "b", "c", "d", "e"]
let array2 = ["a", "c", "d"]
array1 = array1.filter { !array2.contains($0) }

Answer 2

最简单的方法是将两个数组转换为集合,从第一个数组中减去第二个数组,将结果转换为数组并将其分配回array1:

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

请注意,您的代码无效Swift - 您可以使用类型推断来声明和初始化两个数组,如下所示:

var array1 = ["a", "b", "c", "d", "e"]
var array2 = ["a", "c", "d"]

Answer 3

使用索引数组删除元素:

1. 字符串和索引的数组

   let animals = ["cats", "dogs", "chimps", "moose", "squarrel", "cow"]
   let indexAnimals = [0, 3, 4]
   let arrayRemainingAnimals = animals
       .enumerated()
       .filter { !indexAnimals.contains($0.offset) }
       .map { $0.element }
   
   print(arrayRemainingAnimals)
   
   //result - ["dogs", "chimps", "cow"]
   

2. 整数和索引的数组

   var numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
   let indexesToRemove = [3, 5, 8, 12]
   
   numbers = numbers
       .enumerated()
       .filter { !indexesToRemove.contains($0.offset) }
       .map { $0.element }
   
   print(numbers)
   
   //result - [0, 1, 2, 4, 6, 7, 9, 10, 11]
   

使用另一个数组的元素值删除元素

3. 整数数组

   let arrayResult = numbers.filter { element in
       return !indexesToRemove.contains(element)
   }
   print(arrayResult)
   
   //result - [0, 1, 2, 4, 6, 7, 9, 10, 11]
   

4. 字符串数组

   let arrayLetters = ["a", "b", "c", "d", "e", "f", "g", "h", "i"]
   let arrayRemoveLetters = ["a", "e", "g", "h"]
   let arrayRemainingLetters = arrayLetters.filter {
       !arrayRemoveLetters.contains($0)
   }
   
   print(arrayRemainingLetters)
   
   //result - ["b", "c", "d", "f", "i"]