基础操作符号

一、字符串

1、Character 字符类型

let chaA: Character = "好"
let chaB: Character = "B"
let chaC: Character = "\\"

print(chaA, chaB, chaC)

2、String 类型

let str1 = "Hello word"
var str2 = String()
print(str1)
print(str2)

if str2.isEmpty {
    print("字符串是空的")
}

3、字符串长度计算

print("str1字符串长度：\(str1.count)")

4、遍历字符串

for c in str1 {
    print(c)
}

5、链接字符串

let str3 = "my name is lila"
var str4 = str1 + "," + str3
print(str4)
str4 += "."
print(str4)
str4.append("好开心")
print(str4)

6、字符串的插值

let num10 = 10
let message = "\(num10)*2.5=\(Double(num10)*2.5)"
print(message)

7格式化字符串

let hour = 9
let minute = 10
let seconds = 22
let time = String(format: "%02d:%02d:%02d", hour, minute, seconds)
let time2 = String(format: "%01d:%04d:%03d", hour, minute, seconds)
print(time,time2)

8、字符串截取

let firstSpace = str4.firstIndex(of: " ") ?? str4.endIndex

let subStr1 = str4[..

9、比较字符串

let name1 = "lili"
let y = "lili"
if y == name1 {
    print("一样的")
}

10、比较字符串前缀后缀

let httpStr = "https://swift.com.cn"
if httpStr.hasPrefix("http") {  //前缀
    print("http")
}
if httpStr.hasSuffix("cn") {    //后缀
    print("com")
}

二、数组

1、定义数组

//定义一个string类型的数组
var arr1:Array
var arr2:[String]

2、创建空数组

var someInts = [Int]()

3、使用字面量构造数组

let names:[String] = ["lisa", "haojie", "sande"]
let arr3 = ["haozi", 17] as [Any]
print(arr3)

4、数组相加

arr1 = ["老大", "老二"]
arr2 = ["男", "女"]
var arr4 = arr1 + arr2
print(arr4)

5、数组长度、遍历

print(arr4.count)
for name in arr4{
    print(name)
}

6、增加删除

arr4.append("ss")
print(arr4)
arr4.insert("aa", at: 2)
print(arr4)
arr4.remove(at: 0)
print(arr4)
arr4.removeLast()
print(arr4)
arr4.removeFirst()
print(arr4)
arr4.removeAll()
print(arr4)

7、使用下标法修改数组元素

var arr5 = arr3 + arr2
print(arr5)
arr5[0] = "ssssss"
print(arr5)

三、字典与集合

1、创建字典

var dic1:Dictionary = ["name":"lili","age":"18"]

2、增加、替换

var dic2:Dictionary = ["name":"lili","age":18] as [String: Any]
dic2["name"] = "ak47"
print(dic2)

dic2["sex"] = "man"
print(dic2)

3、合并

var dic3 = ["title":"heheheheh"]
for (k,v) in dic3 {
    dic2[k] = v
}
print(dic2)

dic2.removeValue(forKey: "sex")

print(dic2.keys)
print(Array(dic2.keys))
print(dic2.values)
print(Array(dic2.values))