for循環(huán)
Swift提供了兩種for循環(huán)語句,一種是C語言的for循環(huán):條件遞增,這種方式在SWift3.0中遺棄了,現(xiàn)在Swift主要推薦for-in循環(huán)
//在for-in語句中,..<符號表示數(shù)組范圍0~10之間,但是并不包含10,如果循環(huán)中包含10,可以使用...10
for index in 0..<10 {
print("index:\(index)")
}
//循環(huán)遍歷數(shù)組
let names = ["小明","小紅"]
for index in names {
print("name:\(index)")
}
//遍歷元組
let yuanz = [(12,"age"),(13,"age")]
for index in yuanz {
print("name:\(index.0)")
}
//遍歷字典
var dic=["name":"小明","age":"12"]
for index in dic {
print("index:\(index)")
}
while循環(huán)語句
Swift的while循環(huán)語句,和OC的while語句非常的相似,用于重復(fù)執(zhí)行某個(gè)代碼塊
var index = 0
while index<5
{
index+=1
print("index:\(index)")
}
repeat-while循環(huán)語句(do-while語法一致)
var a=0
repeat
{
a+=1
print("a:\(a)")
}
while a<5
if條件判斷語句
if(3<4){
print("呵呵")
}
switch條件判斷語句
let time = 10
switch time {
case 9:
print("這是9")
case 10:
print("這是10")
case 11,12,14:
print("這是毛線")
default:
print("這是毛線")
}
continue語句
for index in 0...10 {//打印的結(jié)果是沒有3的
if index==3 {
continue
}
print("index:\(index)")
}
fallthrough語句
通過該語句，可以允許Swift代碼在執(zhí)行完一個(gè)case分支后,調(diào)到下一個(gè)case中
let age = 10
switch age {
case 9:
print("這是9")
fallthrough
case 10:
print("這是10")
fallthrough
case 11,12,14:
print("這是毛線")
default:
print("這是毛線")
}
