Swift Learning Day Sixth: arrays

An introduction to array arrays

• An array is an ordered set of elements of the same type
• The collection elements in the array are ordered and can recur
• Arrays in Swift
  • The swift array type is an array and is a generic collection

Initialization of the array

• Array partitioning: mutable arrays and immutable groups
  • Arrays that use let adornments are non-variable groups
  • Arrays that are decorated with VAR are mutable arrays

// 定义一个可变数组,必须初始化才能使用var array1 : [String] = [String]()// 定义一个不可变数组let array2 : [NSObject] = ["why", 18]

• You can use one of the following statements when declaring an array type

var stuArray1:Array<String>var stuArray2: [String]

• The declared array needs to be initialized to be used, and the array type is often initialized at the same time as the declaration.

// 定义时直接初始化var array = ["why", "lnj", "lmj"]// 先定义,后初始化var array : Array<String>array = ["why", "lnj", "lmj"]

Basic operation of an array

// 添加数据array.append("yz")// 删除元素array.removeFirst()// 修改元素array[0] = "why"// 取值array[1]

Traversal of an array

// 遍历数组for i in 0..<array.count { print(array[i])}// forin方式for item in array { print(item)}// 设置遍历的区间for item in array[0..<2] { print(item)}

Merging of arrays

// 数组合并// 注意:只有相同类型的数组才能合并var array = ["why", "lmj","lnj"]var array1 = ["yz", "wsz"]var array2 = array + array1;// 不建议一个数组中存放多种类型的数据var array3 = [2, 3, "why"]var array4 = ["yz", 23]array3 + array4

Import UIKit//1. Definition of Arrays//Immutable Group (let) and variable array (VAR)//1> Non-variable groupLet array = [" Why","LMJ","LNJ","YZ"]//2> variable Array//var Arraym = array<string> ()var Arraym =[String] ()//2. Operation of variable array (add and revise)//2.1. Adding elementsArraym.append (" Why") Arraym.append ("YZ") Arraym.append ("LMJ") Arraym.append ("LNJ")//2.2. Deleting an elementArraym.remove (at:0) Arraym//2.3. Modifying elementsarraym[1] =" Why"Arraym//2.4. Get an element of a subscript valuearraym[0]//3. Iterating through an array//Common: Subscript interval traversal forIinch 0.. <arraym.count {print (arraym[i])} forNameinchArraym {print (name)}//not common forIinch 0.. <2{print (arraym[i])} forNameincharraym[0.. <2] {print (name)}//4. Merging of arrays//For name in array {//arraym.append (name)//}//Arraym//in Swift if the two array types are exactly the same, you can add to mergeLet Resultm = Arraym + array

Swift Learning Day Sixth: arrays