区间

• 开区间 0..<3 ---》0 1 2
• 闭区间 0...3---》0 1 2 3

for循环

基础for循环

for i in 0...3 {
    print(i)
}
let names = ["wpp","yuanli","mosi"]
for i in names {
    print(i)
}
控制台：
0
1
2
3
wpp
yuanli
mosi

• i 默认是let

let names = ["wpp","yuanli","mosi"]
for i in 0..<names.count {
    print(names[i])
}

for-range

let range = 0...3
for i in range {
    print(i)
}

for-区间运算符用在数组上

let names = ["wpp","yuanli","mosi"]
print(names)
print(names[0..<3])
print(names[0...])
print(names[1...])

控制台：
["wpp", "yuanli", "mosi"]
["wpp", "yuanli", "mosi"]
["wpp", "yuanli", "mosi"]
["yuanli", "mosi"]

for name in names[0..<3] {
    print(name)
}

控制台：
wpp
yuanli
mosi