https://learnxinyminutes.com/docs/ruby/
Pry - IRB alternative
Hello World
变量
局部变量
以小写字母或 _ 开头
实例变量
以 @ 开头
类变量
以 @@ 开头
全局变量
以 $ 开头
伪变量
self
true
false
nil - null/undefined
__FILE__ - 当前源文件的名字
__LINE__ - 当前行数
算符
数学算符
+ - * / % **
比较算符
== != > < >= <=
<=> - a<=>b a=b 返回0，a>b 返回1，a<b 返回-1
===
.eql? 值和类型都相同时返回true
.euqal? 两边为同一个对象返回true
赋值算符
= += -= *= /= %= **=
位运算符
& | ~ ^ >> <<
逻辑算符
and or not && || !
三目算符
?:
Range算符
.. - (1..5) 1, 2, 3, 4, 5
... - (1...5) 1, 2, 3, 4
defined?
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| defined? variable # True if variable is initialized
defined? foo # => "local-variable"
defined? $_ # => "global-variable"
defined? bar # => nil (undefined)
defined? method_call # True if a method is defined
defined? puts # => "method"
...
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Dot “.” and Double Colon “::”
注释
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| # 注释
=begin
多行注释
=end
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控制语句
if
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| if conditional [then]
code...
[elsif conditional [then]
code...]...
[else
code...]
end
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case
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| case expression
[when expression [, expression ...] [then]
code ]...
[else
code ]
end
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while
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| while conditional [do]
code
[return ...]
end
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方法
返回值为最后一个语句的值
调用方法可以不加括号
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| def method_name [( [arg [= default]]...[, * arg [, &expr ]])]
expr..
end
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模块
打包类，方法，常量
数据结构
Array
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| arr = [1, 2, 3, 4, 5]
arr[0]
arr.each do |i|
puts i
end
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Hash
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| colors = {'red'=> 0xf00, 'green'=> 0x0f0, 'blue'=> 0x00f}
colors['red']
colors.each do |k, v|
print k, " is ", v, "\n"
end
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Range
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| (10..15).each do |n|
print n, ' '
end
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OOP
Class
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| class Customer
@@no_of_customers = 0
def initialize(id, name, addr)
@cust_id = id
@cust_name = name
@cust_addr = addr
end
def hello
puts "Hello Ruby!"
end
# accessor methods
def getName
@cust_name
end
# setter methods
def setName=(value)
@cust_name = value
end
end
cust1 = Customer.new("1", "John", "Wisdom Apartments, Ludhiya")
cust1.hello
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| class Human
def initialize(name)
@name = name
end
# same as getter/setter
attr_accessor :name
end
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To make the variables available from outside the class, they must be defined within accessor methods
Similar to accessor methods, which are used to access the value of the variables, Ruby provides a way to set the values of those variables from outside of the class using setter methods
文件
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| open('test.txt', 'w') do |file|
file.puts('line one.')
file.puts('line two.')
end
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Rake
Ruby Make
带参数的任务:
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| task :new, [:name] do |task, args|
ruby "_scripts/new_post.rb #{args.name}"
end
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