中整個早上都忙著作業,看來是假期懶了一下現在現眼報吧哈哈。在上課之前發一下Ruby 的首章,算是倉促的開始吧。

puts

puts "Once upon a time...

there's a self learn programmer...."   #okay

puts

"Once upon a time...

there's a self learn programmer...."  # output: *blank*

所以Ruby 是case-sensitive 咯?但在網上卻是這樣說:“Whitespace characters such as spaces and tabs are generally ignored in Ruby code, except when they appear in strings. ”(Tutorial Point)。所以,我們推斷 Ruby command 是不可以被分開的。

puts vs print

puts "Hello World"  #auto-append "\n"

print "I am in "    #not appending "\n"

print "campus"

output:

Hello World

I am in campus

啊,要去上課了,待續...

https://www.tutorialspoint.com/ruby/ruby_comments.htm

BEGIN{} & END{} Priorities

puts "in the middle, even written in front?! "

BEGIN{
puts "prog initialize"
}

END{
puts "just before prog termination"
}

output:

prog initialize

in the middle, even written in front?!

just before prog termination

Block commenting

=begin
block comment
instead of using #
=end

Class in Ruby

#in Ruby, everything treated as object

 #in Ruby, everything treated as object 

 $ monthly_customers = 0; 

 class Customer
     @@no_of_customers = 0;         #class var: static DM: all obj share 1 copy

     #member function in ruby class
     def initialize(id, name, addr)    #initialize: the reserved method for constructors
 #lowercase letters for method name
     @cust_id = id    #instance var == DM
     @cust_name = name
     @cust_addr = addr
     end 

     def modify_addr(addr2)
     ::Customer.instance_variable_get(:@cust_addr) = addr2    #modify instance var in same class
     end 

 end

 cust1 = Customer.new(", "Amy", "CauswayBay, HK")
 cust2 = Customer.new;
 p cust2.instance_variable_get(:@cust_id)    #nil: access uninitialized instance variable
 cust2.initialize(", "Timonthy", "Kwai Shing")
 p cust2.instance_variable_get(:@cust_id)    # "02"

差不多要上課了,待續...

https://www.tutorialspoint.com/ruby/ruby_variables.htm
https://www.tutorialspoint.com/ruby/ruby_class_case_study.htm

Global variable in Ruby

$global_variable = "Hello kitty"  #define a global var
class Class1
  def print
    puts "Global variable is: #$global_variable"    #access global var
  end
end   #to finish class definition

class1obj = Class1.new
class1obj.print   #no global fnc in ruby: fnc involved by obj only

Local variable, constant & execution order

$global_variable = "Hello kitty"  #define a global var
class Class1
  @@object_Counter = 1    #no space btw '@@' and identifier name
  FIXED_VALUE = 100     #const var starts with capital, local var starts with lower case 

  def print
    @local_var = "Hello global"
    puts "Global variable is: #$global_variable"    #access global var
    puts "Instance varable ~ DM: #@local_var"     #access instance var
    puts "Existing objects = #@@object_Counter"
  end

  puts "when local variable out of scope: #@local_var"
  # codes defined out of any class method executed first: ~ global MF

  puts "The constant in class : #{FIXED_VALUE}"     #access constant  

end   #to finish class definition

class1obj = Class1.new
class1obj.print   #no global fnc in ruby: fnc involved by obj only

output:

when local variable out of scope:
The constant in class : 100
Global variable is: Hello kitty
Instance varable ~ DM: Hello global
Existing objects = 1
=> nil

to be continued...

Ruby01: Beginner的更多相关文章

  1. A Beginner's Guide to Paxos

    Google Drive: A Beginner's Guide to Paxos The code ideas of Paxos protocol: 1) Optimistic concurrenc ...

  2. Beginner's Guide to Python-新手指导

    Refer English Version: http://wiki.python.org/moin/BeginnersGuide New to programming? Python is free ...

  3. [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之纹理Textures

    [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之纹理Textures 本篇分享一下第6个已完工的视频,即<beginner Graphics ...

  4. [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之网格Meshes

    [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之网格Meshes 本篇分享一下第5个已完工的视频,即<beginner Graphics – ...

  5. [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之材质了解Materials

    [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之材质了解Materials 既上一篇分享了中文字幕的灯光介绍Lights后,本篇分享一下第3个已完工 ...

  6. [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之灯光介绍Lights

    [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之灯光介绍Lights 既上一篇分享了中文字幕的摄像机介绍Cameras后,本篇分享一下第2个已完工的 ...

  7. [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之摄像机介绍Cameras

    [我给Unity官方视频教程做中文字幕]beginner Graphics – Lessons系列之摄像机介绍Cameras 最近得到一些Unity官方视频教程,一看全是纯英文的讲解,没有任何字幕或者 ...

  8. 翻译:Lisp Style Tips for the Beginner - Heinrich Taube

    原文:Lisp Style Tips for the Beginner 本篇文章是一篇非正式的摘要,旨在帮助新手写出高效.易读的Lisp代码. 1 赋值   1.1 避免使用eval.赋值是Lisp内 ...

  9. A Beginner's Guide To Understanding Convolutional Neural Networks(转)

    A Beginner's Guide To Understanding Convolutional Neural Networks Introduction Convolutional neural ...

随机推荐

  1. 持续集成篇-- SonarQube代码质量管理平台的安装

    视频教程:http://www.roncoo.com/course/view/85d6008fe77c4199b0cdd2885eaeee53 IP:192.168.4.221 环境:CentOS 6 ...

  2. linux下安装telnet

    1:yum install telnet-server 2:编辑设置 /etc/xinetd.d/telnet ,将disable= yes设置成disable= no 3:service  xine ...

  3. 手把手教你 基础 整合最优雅SSM框架:SpringMVC + Spring

    我们看招聘信息的时候,经常会看到这一点,需要具备SSH框架的技能:而且在大部分教学课堂中,也会把SSH作为最核心的教学内容. 但是,我们在实际应用中发现,SpringMVC可以完全替代Struts,配 ...

  4. [leetcode-625-Minimum Factorization]

    Given a positive integer a, find the smallest positive integer b whose multiplication of each digit ...

  5. 【Android Developers Training】 56. 更效率地加载大图片

    注:本文翻译自Google官方的Android Developers Training文档,译者技术一般,由于喜爱安卓而产生了翻译的念头,纯属个人兴趣爱好. 原文链接:http://developer ...

  6. Thrift总结(二)创建RPC服务

    前面介绍了thrift 基础的东西,怎么写thrift 语法规范编写脚本,如何生成相关的语言的接口.不清楚的可以看这个<Thrift总结(一)介绍>.做好之前的准备工作以后,下面就开始如何 ...

  7. 常见的JQuery应用举例

    在学习JS之后,JQuery(以下简称JQ)为我们提供了一种更加便捷和简单的操作模式,利用它开发人员将更为高效的进行工作,下面将一些常见的问题进行举例. 1.点击某处弹出提醒,例如某些游戏在注册时会弹 ...

  8. 程序员必须知道的六大ES6新特性

    二 .字符串扩展 1.传统上,JavaScript只有indexOf方法,可以用来确定一个字符串是否包含在另一个字符串中.ES6又提供了三种新方法. includes():返回布尔值,表示是否找到了参 ...

  9. Azure SQL Database (23) Azure SQL Database Dynamic Data Masking动态数据掩码

    <Windows Azure Platform 系列文章目录> 我们在使用关系型数据的时候,有时候希望: - 管理员admin,可以查看到所有的数据 - 普通用户,某些敏感字段,比如信用卡 ...

  10. Java学习笔记之集合

    集合(Collection)(掌握) (1)集合的由来? 我们学习的是Java -- 面向对象 -- 操作很多对象 -- 存储 -- 容器(数组和StringBuffer) -- 数组而数组的长度固定 ...