Array(数组):顺序且有序的集合类型，Ruby中使用方括号来获取数组元素，索引使用数字，从0开始
Hash(哈希or散列):使用键值操作的集合类型，哈希中的索引不局限于使用数字，Hash中的索引也被称为键，使用花括号包含键值对的形式表示
Symbol(符号):Ruby中特有的数据类型，rails中经常用到，使用symbol会比使用字符串更有效率，比如“是否相等”这类问题，字符串是按字母一个一个的比较，而symbol只需进行一次操作，适合用来作为Hash的键（索引）
数组 数组的创建 # 使用[]来创建数组 2.7.2 :002 > nums = [1,2,3,4,5] => [1, 2, 3, 4, 5] 2.7.2 :003 > strs = ["a","b","c"] => ["a", "b", "c"]
# 使用Array.new 2.7.2 :004 > a = Array.new => [] 2.7.2 :005 > p a [] => [] 2.7.2 :006 > a =Array.new(5) => [nil, nil, nil, nil, nil] 2.7.2 :007 > a =Array.new(5,0) => [0, 0, 0, 0, 0]
# %w创建不包含空白的字符串数组，%i创建元素为符号的数组 2.7.2 :008 > lang = %w(Ruby java python ssm nginx docker) => ["Ruby", "java", "python", "ssm", "nginx", "docker"] 2.7.2 :009 > p lang ["Ruby", "java", "python", "ssm", "nginx", "docker"] => ["Ruby", "java", "python", "ssm", "nginx", "docker"] 2.7.2 :010 > lang = %i(Ruby java python ssm nginx docker) => [:Ruby, :java, :python, :ssm, :nginx, :docker] 2.7.2 :011 > p lang [:Ruby, :java, :python, :ssm, :nginx, :docker] => [:Ruby, :java, :python, :ssm, :nginx, :docker]
# 使用to_a方法把其他对象转换为数组 2.7.2 :012 > smartphone = {xiaomi: "小米",huawei: "华为"} => {:xiaomi=>"小米", :huawei=>"华为"} 2.7.2 :016 > t = smartphone.to_a => [[:xiaomi, "小米"], [:huawei, "华为"]] 2.7.2 :018 > t.is_a? Array => true
# 对用逗号或者空白隔开的字符串使用split方法 2.7.2 :019 > text = "one","two","three".split(',') => ["one", "two", ["three"]] 2.7.2 :020 > text = "one,two,three".split(',') => ["one", "two", "three"] 2.7.2 :022 > p text ["one", "two", "three"] => ["one", "two", "three"]
索引的使用 # 通过[]指定索引，获取相应的元素 2.7.2 :023 > a = ["a","b","c","d"] => ["a", "b", "c", "d"] 2.7.2 :024 > a[1] => "b" # 形如a[n..m]，若m比数组长度大，返回的结果与指定的数组最后一个元素是一样的 2.7.2 :025 > a[1..4] => ["b", "c", "d"] # 从某个元素开始，获取多个元素 2.7.2 :026 > a[1,2] => ["b", "c"] # 还可使用at，slice方法
# 使用a[n] = item来替换元素 a = ["a","b","c","d"] a[2,4] = ["C","D","E"] p a output----["a","b","C","D","E"] a = ["a","b","c","d","e","f"] a[2..4] = ["C","D","E"] p a output---- ["a","b","C","D","E","f"]
# 插入元素 irb(main):003:0> a = ["q","s","d"] irb(main):006:0> a[2,0] = ["X","Y"] irb(main):007:0> a => ["q", "s", "X", "Y", "d"]
# 通过多个索引创建数组 irb(main):008:0> a = %w(a b c d e d) irb(main):009:0> a => ["a", "b", "c", "d", "e", "d"] irb(main):010:0> a.values_at(1,3,5) => ["b", "d", "d"]
作为集合与作为列的数组 # 交集&并集 irb(main):011:0> ary = ["a","b","c"] irb(main):012:0> ary1 = ["b","c","d"] irb(main):013:0> ary & ary1 => ["b", "c"] irb(main):014:0> ary | ary1 => ["a", "b", "c", "d"] irb(main):015:0> ary1-ary => ["d"]
irb(main):016:0> ary+ary1 => ["a", "b", "c", "b", "c", "d"]
# 对于数组开头的元素 irb(main):022:0> a => ["a", "b", "c", "d", "e", "d", "f"] irb(main):023:0> a.unshift("1") => ["1", "a", "b", "c", "d", "e", "d", "f"] irb(main):024:0> a.shift => "1" irb(main):025:0> a => ["a", "b", "c", "d", "e", "d", "f"] # 对于数组末尾的元素 irb(main):026:0> a => ["a", "b", "c", "d", "e", "d", "f"] irb(main):027:0> a.push("df") => ["a", "b", "c", "d", "e", "d", "f", "df"] irb(main):028:0> a.pop => "df" irb(main):029:0> a => ["a", "b", "c", "d", "e", "d", "f"]
主要的数组方法 irb(main):033:0> a = [1,2,3,4,5,1,3,6] # 数组开头添加元素 irb(main):034:0> a.unshift(12) => [12, 1, 2, 3, 4, 5, 1, 3, 6] # 数组末尾添加元素 irb(main):035:0> a << 980 => [12, 1, 2, 3, 4, 5, 1, 3, 6, 980] # 连接两个数组 irb(main):037:0> a.concat([8,3,5]) => [12, 1, 2, 3, 4, 5, 1, 3, 6, 980, 8, 3, 5] irb(main):038:0> a => [12, 1, 2, 3, 4, 5, 1, 3, 6, 980, 8, 3, 5] # 把第2，3，4个元素换为一个0 irb(main):039:0> a[2..4]=0 irb(main):040:0> a => [12, 1, 0, 5, 1, 3, 6, 980, 8, 3, 5] # 1-3的元素换为一个9 irb(main):041:0> a[1,3] = 9 irb(main):042:0> a => [12, 9, 1, 3, 6, 980, 8, 3, 5] ```
irb(main):060:0> a
irb(main):076:0> a
irb(main):116:0> a
irb(main):128:0> b=[[1,2,3],[2,3,4],[3,4,5]]
irb(main):164:0> a
irb(main):182:0> h1 = {“a”=>”b”,”c”=>”d”}
irb(main):188:0> h = Hash.new<main>'
4: from /usr/bin/irb:23:inload’<top (required)>'
2: from (irb):194
1: from (irb):194:infetch’
irb(main):201:0> h3 = Hash.new(1)
irb(main):213:0> h1
irb(main):218:0> h1
irb(main):222:0> h1
irb(main):228:0> h1