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Contents.swift
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Contents.swift
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//: Playground - noun: a place where people can play
import UIKit
var numbers = [1,2,3,4,5]
var vowels = ["A","E","I","O","U"]
var emptyArray = [Int]()
// 数组长度
vowels.count
// 判空
numbers.isEmpty
emptyArray.isEmpty
// 获取元素
vowels[2]
// 数组越界是一个严重的错误
//vowels[-1]
//vowels[5]
// 获取第一个元素和最后一个元素,返回的是可选型
vowels.first
vowels.last
emptyArray.first
if let firstVowel = vowels.first{
print("The first vowel is " + firstVowel)
}
vowels.first!
vowels[vowels.count-1]
// 获取最小,最大值
numbers.minElement()
vowels.maxElement()
// 使用范围
numbers[2..<4]
numbers[2..<numbers.count]
// 包含
vowels.contains("A")
vowels.contains("B")
let letter = "A"
if vowels.contains( letter ){
print("\(letter) is a vowel")
}
else{
print("\(letter) is not a vowel")
}
vowels.indexOf("E")
if let index = vowels.indexOf("E"){
print("E is a vowel in position \(index+1).")
}
else{
print("E is not a vowel.")
}
// 遍历
for index in 0..<numbers.count{
numbers[index]
}
for number in numbers{
print(number)
}
for (index, vowel) in vowels.enumerate(){
print("\(index+1): \(vowel)")
}
// 比较
var oneToFive = [1,2,3,4,5]
numbers == oneToFive
var oneToFive2 = [1,2,4,3,5]
numbers == oneToFive