Swift快速入门（四）

区间运算符

let a = 0... 4 //从0到4 ---- 也称闭区间运算符

 print ("a范围=\(a)")

 let b = 0 ..<4 //从0到3 ---- 也称半闭区间运算符

 print ("b范围= \(b) ")

 let c = - 3 ..< 4 //从-3到3

 print("c范围=\(c)")

 let d = (2.5)..< 4 //从-3到3

 print("d范围=\(d)")

 let e = 1 ... //从1开始到无限大 ---- 也称单边区间运算符

 print("e范围=\(e)")

循环

• for in循环

for index in 0 ..< 5 {//大于等于0，小于5

 print("index1 =\(index)")

}

print("---------------")

for index in stride (from : 0 , to: 10,by: 2){
//从0开始到8结束，不包括10，筛选能够整除2的数**

  print("index2 = \(index) ")

}

 print("---------------")
 
 for index in stride ( from : 0, through :10,by:2){
  //从0开始到10结束，包括10，筛选能够整除2的数
   print("index3 = \(index)")
 }

print("---------------")

• while 循环

var i = 100

while i < 20 0
{
   print( "i 的值为 (i)")
   i = i + 1
}

• repeat...while 循环

var j = 15

repeat{
    print( "j 的值为 (j)")
    j = j + 1
}while j < 20

• 控制语句

1. continue 语句: 立刻停止本次循环迭代，重新开始下次循环迭代。

for index in 0...5{

 if(index == 2 || index == 3){

   continue

}

  print("index4 = \(index)")

}

 print("---------------")

2. break 语句：中断当前循环。

for index in 0...5{

 if(index == 2 || index == 3){

   break

 }

 print("index5 = \(index)")
}