Install

sudo apt install ruby ruby-dev ruby-bundler

root@ubuntu22:~# ruby --version
ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-linux-gnu]

root@ubuntu22:~# bundler --version
Bundler version 2.3.5

===== 默认源
root@ubuntu22:~/ruby# gem sources
*** CURRENT SOURCES ***

https://rubygems.org/

===== 国内源
gem sources --remove https://rubygems.org/
gem sources -a https://mirrors.aliyun.com/rubygems/

Ruby 语法

print "Hello world!\n"
# 输出 p(”hee")
print("hello")
print("\n")
puts "hello"

# 数值对象，字符串对象，时间对象，文件对象，数组对象
# Numeric, String, Array, File
# 局部变量 aa, _aa   常量(readonly) TEST=1  RUBY_VERSION
# 全局变量 $x  实例变量@xx  类变量@@shape
arr = ["a", 2, nil]
arr.each do |item|
  p(item)
end
puts(RUBY_VERSION)
puts(RUBY_PLATFORM)
a=1
b=2;c=3
v=(a>b) ? a : b
puts(v)
# Range.new(1,10)  范围运算符1..10
# 指数**  三元?:
# 值相等 === ,  属于类 p(String === "asdf")

选择循环

# if xx then [] end 可以省略then, if xx then {} elsif then {} else {} end
# unless yy then {}  end  条件为假执行
if true
  puts("bb")
end

case v
  when 1 then
    puts("1")
  when 2 then
    puts("2")
  else
    puts("none")
end


# 循环 times方法, for语句, while, util, loop
# 用{}代替 do end
3.times do |i|
  puts("No. #{i}")
end
10.times { }
for i in 1..10 do
  #
end

arr = ["a", "b", "c", "d"]
for name in arr do
  #
end
arr.each do |name| puts name end

loop do
  # 死循环
  break # next等价continue, redo重复刚才处理
end
while true  do
  # 条件为真
end

until false do
  # 调价为假
end

函数

# 运算符也是方法，有些可以重载
# 实例方法
p "10,2,3".split(",")
p [12,3].index(1)
p 100.to_s  # 转字符串
# 类方法
Array.new
File.open("hello.rb", "r")
Time.now
# 函数方法
sleep(2)
print("hello world")

def hello(name)
  puts "Hello, #{name}"
end

def add(a,b)
  return a + b # 可以省略return
end

def fool(*args)
  # 个数不确定
  # 至少一个参数 def add(a, *args)
end

面向对象

arr=Array.new
p arr
p arr.class
arr = [1,2]
str = "hello world"
p arr.class
p str.class
p str.instance_of?(String)

# 实例变量@xx， 类变量@@yy所有实例共享
class HelloWorld
  @@count = 0
  def initialize(myname="Ruby")
    @name=myname
    @@count+=1
  end

  def hello
    puts "Hello #{@name}  / #{@@count}"
  end
end

hx = HelloWorld.new("Tomas")
hx2 = HelloWorld.new
hx.hello

# 类方法
# class HelloStatic
#   class << self
#     def hello(name)
#       puts "Hello static #{name}"
#     end
#   end
# end

# 类方法2, 类常量
class HelloStatic
  VERSION="v1.0"
end
def HelloStatic.hello(name)
  puts "Hello static #{name}"
end
HelloStatic.hello("Ruby")
puts HelloStatic::VERSION


# 访问级别 public(默认), private, protected
class AccTest
  def hello

  end
  public :hello

  def name

  end
  private :name
end
acc = AccTest.new
acc.hello


# 继承
class ArrayTest < Array
  def[](i)
    super(0)
  end
end
arr = ArrayTest.new([1,2,3])
puts arr[0]
puts arr[1]
puts arr[2]


# 模块， 命名空间
module Std
  STD_VERSION = "v17"  # 模块常量
  def hello

  end
  module_function :hello  # 模块方法
end
Std::hello
puts Std::STD_VERSION

include Std
puts STD_VERSION

异常

begin
  # File.open("aaa.txt")  # IOError
  # 抛出异常, RuntimeError
  raise
  raise("xyzwer")
rescue => ex
  # 错误处理, StandardError及其子类(RuntimeError)
  puts ex.message
ensure
  puts "finally" # 无论是否发生异常
end