Ruby1 数据类型，变量

1. 整数类型: 3,222
2. 小数: 3.14
3. 字符串: hello,world
4. 布尔类型: true(TrueClass),false(FalseClass)
5. 数组: [1,2],["hello","hello world"]
6. Hash(字典): {"name"=>"luo","age"=>24},{:name=>"daoyi",:age=>24}
7. Symbol(符号): :a,:hello,:"hello world"
8. Range: 1..10,1...10(三个点不包括10本身)
9. 正则: /hello/i

String 字符串

a = "hello" #=> hello b = "world" #=> world  a.class #=> String a + " " + b #=> hello world "#{a} #{b}" #=> hello world

string method

"hello world".length #=>11 "hello world".capitalize #=> Hello world "hello world".gsub("world","gril").upcase #=> HELLO GIRL

变量赋值

a = "hello" # => hello a.object_id # => 70353313681980  a.replace("hello2") # => "hello2" a.object_id # => 70353313681980  a = "hello" a.object_id # => 70353313549380

当a 使用replace时候仍然是原本的引用地址，所以Object_id不变
但是当a重新赋值为hello 的时候，a的引用地址发生了变化 object_id就改变了

以!结尾的方法

a = "hello" # => hello a.capitalize # => Hello a # => hello  a.capitalize! #=> Hello a # => Hello

1. ！结尾的方法会改变变量资深
2. 这只是个约束
3. 在Rails中！的方法也被用来表示该方法会抛出异常

以？结尾的方法

a = "hello" # => hello a.is_a?(String) #=> true

1. ？的方法会返回true|false
2. 这只是一个约束

nil

什么是nil

a = nil # => nil a.nil? # => true

在ruby中nil和false都是"不成立"的意思，或者"否"的意思 其他一切都为true

双引号和单引号

a = "hello" # => hello b = 'hello' # => hello  a == b # => true c = "world" # => world a = "hello #{c}" # => hello world a = 'hello #{c}' # => hello /#{c}

双引号中的变量会被解释,单引号不会
反引号，直接运行shell命令

Array

a = [1,2,"hello"] # => [1,2,"hello"] a.length # =>3

数组中可以放置任意类型

array常用方法

a = [1,2,"hello"] a.length # =>3 a.size # =>3  a.first # =>1 a.last # =>hello  b = ["world"] # => ["world"] c = a + b # => [1,2"hello","world"] b *3 # => ["world","world","world"]  c - a # =>["world"]

这些方法并不会改变数组本身

a = [] # => [] a.push(1) # => [1] a.push(2) # => [1,2] a.unshift(3) # => [3,1,2]  a.pop # => 2 a.shift # => 3 a #=> 1

所有这些方法都会改变数组本身

Array 奇技淫巧

a = [] # =>[] a << 3 # =>[3]  a.concat([4,5]) # => [3,4,5] a.index(4) #=> 1 a[0] = 1 # => 1  a.max # => 5 

ruby中的方法

a = 1 # => 1 a + 2 # => 3 

在这里+ 只是一个方法，2是传递给方法的参数
可以解释为 a 拥有 +这样一个方法 2收传递给+方法的参数

Hash

a = {"name" => "luo","age"=>24,"hobbies" => ["coding","video game","music"]} a["name"] # => "luo"

hash是无序的，数组是有序的

Hash 常用方法

a = {"name" => "luo","age"=>24,"hobbies" => ["coding","video game","music"]}  a.keys # => ["name", "age", "hobbies"] a.values # => ["luo", 24, ["coding", "video game", "music"]] a.delete("hobbies") # => ["coding", "video game", "music"] a["cellphone"] = "16666666666" # => "16666666666"

Hash的其他定义方式

a ={name:"luo",age:24,hobbies:["coding","video game","music"]}  # => {:name=>"luo", :age=>24, :hobbies=>["coding", "video game", "music"]}

Json的定义方式，顺应web前端的发展趋势

Symbol

a = :hello # => :hello b = "#{a} world" # => "hello world"  c = :"hello world" # => :"hello world" c.object_id # => 1160948 c = :"hello world" # => :"hello world" c.object_id # => 1160948

Symbol是String的补充，可以看做为字符串来使用，但是Symbol和String在本质上还是不同的，在 Ruby中Symbol经常被用来作为hash的key和一些变化不频繁的字符串来使用

Symbol和hash

a ={:name => "luo",:age=>24,:hobbies =>["coding","video game","music"]} a[:name] # => "luo"

Range

a = 1..10 # => 1..10 a.to_a.size # => 10  b = 1...10 # => 1...10 b.to_a.size # => 9 c = :a..:z # => :a..:z  d = a.to_a + c.to_a # => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, :a, :b, :c, :d, :e, :f, :g, :h, :i, :j, :k, :l, :m, :n, :o, :p, :q, :r, :s, :t, :u, :v, :w, :x, :y, :z]

Regular Expression 正则类型

a =/hello/ # => /hello/ "hello world" =~ a  # => 0  email_re = //A[/w+/-.]+@[a-z/d/-.]+/.[a-z]+/z/i # => //A[/w+/-.]+@[a-z/d/-.]+/.[a-z]+/z/i email_re.match("[email protected]") # => #<MatchData "[email protected]">