1亲善、算數(shù)運(yùn)算符
Swift中的所有基本類型凉袱，我們可以開(kāi)始使用運(yùn)算符將它們放在一起傲宜。運(yùn)算符是像+和這樣的小數(shù)學(xué)符號(hào)-运杭，而Swift擁有大量的數(shù)學(xué)符號(hào)
let firstScore = 12
let secondScore = 4
let total = firstScore + secondScore
let difference = firstScore - secondScore
let product = firstScore * secondScore
let divided = firstScore / secondScore
let remainder = 13 % secondScore
Swift支持運(yùn)算符重載，這是一種很好的說(shuō)法函卒，即運(yùn)算符的作用取決于您使用它的值
let meaningOfLife = 42
let doubleMeaning = 42 + 42
let fakers = "Fakers gonna "
let action = fakers + "fake"
let firstHalf = ["John", "Paul"]
let secondHalf = ["George", "Ringo"]
let beatles = firstHalf + secondHalf
var score = 95
score -= 5
var quote = "The rain in Spain falls mainly on the "
quote += "Spaniards"
Swift是一種類型安全的語(yǔ)言辆憔，這意味著它不會(huì)讓您混合類型。例如报嵌，您不能在字符串中添加整數(shù)虱咧，因?yàn)樗鼪](méi)有任何意義。swift取消++和—锚国。
2腕巡、比較運(yùn)算符
let firstScore = 6
let secondScore = 4
firstScore == secondScore
firstScore != secondScore
firstScore < secondScore
firstScore >= secondScore
由于字符串具有自然的字母順序，因此它們每個(gè)都還適用于字符串：
"Taylor" <= "Swift"
3血筑、條件
let firstCard = 11
let secondCard = 10
if firstCard + secondCard == 2 {
print("Aces – lucky!")
} else if firstCard + secondCard == 21 {
print("Blackjack!")
} else {
print("Regular cards")
}
let age1 = 12
let age2 = 21
if age1 > 18 && age2 > 18 {
print("Both are over 18")
}
4绘沉、三元運(yùn)算符
三元運(yùn)算符是一個(gè)條件煎楣，加上一個(gè)條件，一個(gè)或一個(gè)以上的true或false塊被一個(gè)問(wèn)號(hào)和一個(gè)冒號(hào)分開(kāi)
let firstCard = 11
let secondCard = 10
print(firstCard == secondCard ? "Cards are the same" : "Cards are different")
5车伞、swich語(yǔ)句
let weather = "sunny"
switch weather {
case "rain":
print("Bring an umbrella")
case "snow":
print("Wrap up warm")
case "sunny":
print("Wear sunscreen")
default:
print("Enjoy your day!")
}
最后一種情況default是必需的-因?yàn)镾wift會(huì)確保您涵蓋所有可能的情況择懂，因此不會(huì)錯(cuò)過(guò)任何可能的情況。如果天氣不是下雨另玖，下雪或曬日光困曙，default則將運(yùn)行機(jī)箱日矫。
Swift只會(huì)在每種情況下運(yùn)行代碼赂弓。如果要繼續(xù)執(zhí)行下一種情況，請(qǐng)使用如下fallthrough關(guān)鍵字
switch weather {
case "rain":
print("Bring an umbrella")
case "snow":
print("Wrap up warm")
case "sunny":
print("Wear sunscreen")
fallthrough
default:
print("Enjoy your day!")
}
5哪轿、范圍運(yùn)算符
Swift提供了兩種生成范圍的方式：..<和...運(yùn)算符。半開(kāi)范圍運(yùn)算符翔怎，..<創(chuàng)建范圍不超過(guò)最終值窃诉，但不包括最終值；封閉范圍運(yùn)算符...赤套，創(chuàng)建范圍不超過(guò)最終值飘痛，包括最終值。
例如容握，范圍1..<5包含數(shù)字1宣脉、2、3和4剔氏，而范圍1...5包含數(shù)字1塑猖、2、3谈跛、4和5羊苟。
范圍對(duì)于switch塊很有用，因?yàn)槟梢栽诿糠N情況下使用它們感憾。
let score = 85
switch score {
case 0..<50:
print("You failed badly.")
case 50..<85:
print("You did OK.")
default:
print("You did great!")
}
