Ruby 数据类型，变量
- 整数类型:
3,222 - 小数:
3.14 - 字符串:
hello,world - 布尔类型:
true(TrueClass),false(FalseClass) - 数组:
[1,2],["hello","hello world"] - Hash(字典):
{"name"=>"luo","age"=>24},{:name=>"daoyi",:age=>24} - Symbol(符号):
:a,:hello,:"hello world" - Range:
1..10,1...10(三个点不包括10本身) - 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
- ！结尾的方法会改变变量资深
- 这只是个约束
- 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
- ？的方法会返回true|false
- 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("111@qq.com") # => #<MatchData "111@qq.com">
