for 循环
for ... in ... 循环
forindexin 1...5{
println("\(index)times 5 is * )
}
// 1 times 5 is 5
// 2 times 5 is 10
// 3 times 5 is 15
// 4 times 5 is 20
// 5 times 5 is 25
letbase= 3
power10
varanswer1
for _ in...*=base
to the power of is// prints "3 to the power of 10 is 59049"
names= ["Anna","Alex""Brian""Jack"]
namein names {
println"Hello,name!"// Hello,Anna!
numberOfLegs"spider":8"ant"6"cat"4for(animalNamelegCount)innumberOfLegs printlns have legs"// spiders have 8 legs
// ants have 6 legs
// cats have 4 legs
characterin "Hello" character// H
// e
// l
// o
For-Condition-Increment
for var0;< 3; ++"index is// index is 0// index is 1
// index is 2
:Int
}
// index is 2
"The loop statements were executedtimes"// prints "The loop statements were executed 3 times"
while 循环
square0
diceRollwhile< finalSquare // roll the dice
if++==7 { diceRoll 1 // move by the rolled amount
square+=diceRoll
ifboard.count// if we're still on the board,move up or down for a snake or a ladder
[]
}
}
println"Game over!")
// move by the rolled amount
}square finalSquare
)
条件语句
if
iftemperatureInFahrenheit<= 32 "It's very cold. Consider wearing a scarf."// prints "It's very cold. Consider wearing a scarf."
=40
else"It's not that cold. Wear a t-shirt."// prints "It's not that cold. Wear a t-shirt."
90
else iftemperatureInFahrenheit >= 86 {
"It's really warm. Don't forget to wear sunscreen."// prints "It's really warm. Don't forget to wear sunscreen."
72
if <= } else if }
switch
let someCharacter : Character = "e"switch someCharacter {
case "a" , "e" , "i" , "o" , "u" :
println ( " \( someCharacter ) is a vowel" )
case "b" , "c" , "d" , "f" , "g" , "h" , "j" , "k" , "l" , "m" ,
"n" , "p" , "q" , "r" , "s" , "t" , "v" , "w" , "x" , "y" , "z" :
println ( " \( someCharacter ) is a consonant" )
default :
println (someCharacter) is not a vowel or a consonant")
} //
prints "e is a vowel"
没有隐性陷入
let anotherCharacter : Character = "a"switch anotherCharacter {
case "a" :
case "A" :
println ( "The letter A" )
default :
println"Not the letter A"// this will report a compile-time error
范围匹配
let count = 3_000_000_000_000countedThings = "stars in the Milky Way"
naturalCount: String
switch case :
naturalCount = "no"
"a few"
9:
"several"
case 1099 "tens of"
100999 "hundreds of"
1000999_999 "thousands of"
default "millions and millions of"
}
// prints "There are millions and millions of stars in the Milky Way."
元组匹配
somePoint = (case ():"(0,0) is at the origin"(_"(somePoint.,0) is on the x-axis") is on the y-axis"(-2):
) is inside the Box")
:
) is outside of the Box" //
prints "(1,1) is inside the Box"
值绑定
let anotherPoint = (2,0)
switch anotherPoint {
case (let x,0):
println("on the x-axis with an x value of \(x)")
case (0,let y):
println("on the y-axis with a y value of ycase let x "somewhere else at ()"}
// prints "on the x-axis with an x value of 2"
附加条件
yetAnotherPoint ) where x == y) is on the line x == y"== -) is on the line x == -y") is just some arbitrary point"// prints "(1,-1) is on the line x == -y"
控制流变换语句
continue
puzzleInput "great minds think alike"
puzzleOutput ""
for character in character case "a""e""i""o""u"" "continue
+= character
}
break
numberSymbolCharacter "三" // Simplified Chinese for the number 3
possibleIntegerValueInt?
numberSymbol "1""١""一""๑"possibleIntegerValue 1
"2""٢""二""๒"2
"3""٣""三""๓"3
"4" "٤" "四""๔"possibleIntegerValue 4
:
break
}
iflet integerValue = {
"The integer value of is \(integerValue)
} else {
"An integer value could not be found for //
prints "The integer value of 三 is 3."
fallthrough
integerToDescribe 5
description "The number integerToDescribeis"
711131719+= " a prime number,and also"
fallthrough
+= " an integer."
}
description// prints "The number 5 is a prime number,and also an integer."
标签语句
gameLoop: while square != finalSquare if diceRoll == 7 switch + case finalSquare// diceRoll will move us to the final square,so the game is over
break gameLoop
case let newSquare where newSquare > // diceRoll will move us beyond the final square,so roll again
continue gameLoop
default:
// this is a valid move,so find out its effect
square diceRoll
square += ]
}
}
)
原文链接：https://www.f2er.com/swift/327378.html