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基础操作符号

基础操作符号

作者: 阳vs阴 | 来源:发表于2021-03-19 19:05 被阅读0次

    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[..<firstSpace]
    print(subStr1)
    
    let someRange = str4.range(of: "lila")
    let subStr3 = str4[someRange!]
    print(subStr3)
    print(str4[..<someRange!.lowerBound])
    print(str4[someRange!.upperBound...])
    
    let someRange3 = str4.range(of: "好开心")
    print(str4[..<someRange3!.lowerBound])
    print(str4[someRange3!.upperBound...])
    
    
    
    let subStr2 = str4.split(separator: " ", maxSplits: 10, omittingEmptySubsequences: true)
    print(subStr2)
    

    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<String>
    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<String, String> = ["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))
    

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