Swif学习总结 基本数据类型（一）

let常量与 var变量
var point = (10 , 20)
print(point)

let website:String = "ww.ic.c"

print("nihao"+website)

var a = 3
if a == 1{
    print(a)
}

for index in 1...10{
    index
}

for index in 0..<10{
    index
}

let score = 90
switch score{
    
case 0:print("12")
case 1..<60:print("123")
case 90:print("\(score)")
default:
    ()
}

let points: (x:Int , y:Int) = (1, 2)

switch points{

case (_,2):print("\(points.x), \(points.y)");
    fallthrough
default:
    ()
    
}

let yuanzu: ( x:Int , y:Int) = (1,23)

findasd:for m in 1...300{

    if m == 6{
        break findasd
    }
}

let age = 19

if case 10...19 = age where age >= 18 {
    print("you are a teenager and in a college")
}

var strs = "hello world"

for c in strs.characters{
    
//    print(c)
}

let mark:Character = "!"
strs + String(mark)
strs.append(mark)

let enlish:Character = "a"
let chinese:Character = "你"
let collguy:Character = "\u{1f60e}"

var str = "Hello, playground"
//str += " ::>"
//print(str)

str.characters.count

let start:String = "hello world"
let startIndex = start.startIndex
//索引后移动6
start[startIndex.advancedBy(6)]
//输出前一个字符
//start[startIndex.predecessor()]
//输出后一个字符
start[startIndex.successor()]

let startIndexstr = str.startIndex
let spaceIndex = startIndexstr.advancedBy(6)
let endIndex = str.endIndex
str[endIndex.predecessor()]

str[startIndexstr..<spaceIndex]
let range = startIndexstr..<spaceIndex.predecessor()

str.replaceRange(range, with: "Hi")
str.appendContentsOf("!!!")
str.insert("g", atIndex: str.endIndex)
str.removeAtIndex(str.endIndex.predecessor())
str

str.removeRange(str.endIndex.advancedBy(-2)..<str.endIndex)
str.uppercaseString
str.lowercaseString

//是否包含特定的字符 
前缀是否相同  后缀是否相同
str.containsString("hello")
str.hasPrefix("he")
str.hasSuffix("ft")
let s = "one third is \(1.0/3.0)"

//NSString（不是基于UniCode的）
与String的相互转化
let s2:String = NSString(format: "ont third is %.2f", 1.0/3.0) as String

var s3:NSString = "one third is 0.33"
s3.substringFromIndex(4)
s3.substringToIndex(5)
//开始的位置3截取的长度6
s3.substringWithRange(NSMakeRange(3, 6))

let s4 = "