iOS_Swift_条件语句

if语句

var text = 100
var res:String

if text >= 90 {
res = "优秀"
}else if text >= 80{

res = "良好"
}

for循环

var sum = 1
var i = 1
i+=1
print(i)
for var i = 0; i<10 ; i+=1 {
print(i)
}
for i in 0...10 {
print(i)
}

//break 终止,continue跳过
var  array = [1,2,3,4,5,6]
for (index,value) in array.enumerate() {
print(index, value)
if index == 4 {
break
}
}
var str : String

for a in 1...10 {
switch a {
case 1:
str = "a"
default:
str = "b"
}
}

Switch

//可以匹配范围
let x = 100
switch x {
case 1...9:
print("个位数")
default:
print("其他")
}

//元组
let point = (10,10)
switch point {
case (0,0):
print("坐标原点")
default:
print("其他")
}

//值绑定  模式(结构)匹配
/*
匹配y=10 的值 将x的值赋值给x
*/
switch point {
case (let x , 10):
print(x)
case let( x,  y) where x==1:
print(x,y)
//条件为x==1

default:
print("无")
}