Swift--06数组字典

print("数组字典")

//数组：Array

var a1: [Int] = []

if a1.isEmpty {

print("数组为空")

a1 = [1,2,3,4,5]

}

//长度计算

print(a1.count)

//添加元素

a1 += [6]

a1.append(7)

a1.insert(8,at: 0)

print(a1)

//删除

//删除第一个

a1.removeFirst()

//删除前几个

a1.removeFirst(2)

//删除指定索引的元素

a1.remove(at: 3)

//删除最后一个

a1.removeLast()

//删除所有

a1.removeAll()

print(a1)

var a2 = ["one","two","three","four"]

//修改指定索引的元素

a2[0] = "ling"

a2[1...3] = ["er","san","si"]

print(a2)

//是否包含元素

print(a2.contains("two"))

//遍历数组

for ele in a2 {

print(ele)

}

for (index,value) in a2.enumerated() {

print("a2[\(index)] = \(value)")

}

//var array: NSArray = [123,456]

//字典：Dictionary

var d1:[Int: String] = [1:"one",2:"two"]

//添加元素

d1[3] = "three"

d1.updateValue("four",forKey: 4)

print(d1)

//删除元素

d1.removeValue(forKey: 1)

//d1.removeAll()

//所有键

for key in d1.keys {

print(key)

}

for value in d1.values {

print(value)

}

//遍历字典

for (key,value) in d1 {

print("\(key):\(value)")

}

var aaa: NSMutableArray = []

aaa.add("abc")

aaa.add(250)

#if true

//将获取的元素强制转换为String类型，若能够则转换成功

var bbb: String = aaa[0] as! String

#else

//若不能转换成功，则会出现崩溃

var bbb: String = aaa[1] as! String

#endif

print(bbb)

#if false

//将获取的元素转换为Int?类型，若能够则转换成功

var ccc: Int? = aaa[1] as? Int

//若不能转换成功，则返回nil

var ccc: Int? = aaa[0] as? Int

print(ccc)

原文地址：https://www.jb51.cc/swift/321708.html