Ruby introduction part1
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This document provides an introduction and overview of the Ruby programming language. It discusses installing Ruby on Windows and Mac systems, data types including numbers, strings, and arrays. It also covers variables, arrays, iterators, methods including built-in and user-defined methods, and flow control including if/else conditional statements and while loops. The document encourages comments and feedback.
![Variables, Arrays, and Iterators
Arrays
[ele1, ele2, ele3]
Some array methods
.pop
.push
.join(‘join string’)
.last
.length](https://image.slidesharecdn.com/rubyintroduction-part1-121118111542-phpapp02/85/Ruby-introduction-part1-7-320.jpg)
![Variables, Arrays, and Iterators
There is a special array method : each
iterator
An array with 3 elements
color= [‘R', 'G', 'R']
color.each do | c | | c | = variable in this
puts “color=” + c do…end block
end
Output=
color=R
color=G
color=B](https://image.slidesharecdn.com/rubyintroduction-part1-121118111542-phpapp02/85/Ruby-introduction-part1-8-320.jpg)
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Ruby introduction part1
- 1. A Brief Introduction to Ruby : P1 (Book Review of “Learn to Program”) Brady Cheng http://bradyisstudying.blogspot.tw/
- 2. Agenda Install Comment Data Types Variables, Arrays, and Iterators Methods Flow Control
- 3. Install For Windows http://rubyinstaller.org/ For Mac Build-in I strongly recommend you to use Mac or Linux to develop Ruby programs. But in this tutorial, I am gonna use Windows since I am stiff-necked guy
- 4. Comment Comment in Ruby is similar to Perl Ruby Perl # comment a line # comment a line =begin =pod Comment a block Comment a block =end =cut
- 5. Data Types Numbers puts 1+2 #3 Integer print puts 2*3 #6 puts 5-8 #-3 Float puts 9/2 #4 Letters puts 9.to_f/2 #4.5 String Cast to float -------------------------- puts ‘Enter a string’ #Enter a string More: puts gets.chomp #input from keyboard .to_i puts 'ha'*3 #hahaha .to_s puts=<STDOUT> Repeat 3 times gets=<STDIN> chomp=delete last char
- 6. Variables, Arrays, and Iterators In C/C++, we write int a = 1; in Perl, we write $a = 1; in Ruby… a= 1 Yes, just write a a= 1 b = ‘2’ c = a.to_s + b #12 Cast a to string Add(+) = conj strings
- 7. Variables, Arrays, and Iterators Arrays [ele1, ele2, ele3] Some array methods .pop .push .join(‘join string’) .last .length
- 8. Variables, Arrays, and Iterators There is a special array method : each iterator An array with 3 elements color= [‘R', 'G', 'R'] color.each do | c | | c | = variable in this puts “color=” + c do…end block end Output= color=R color=G color=B
- 9. Methods If objects(variables, arrays, …) are nouns in English, then methods are verbs! int=noun We say “int, convert to string” to_s=verb int.to_s Sometimes we just say a verb without any noun, ie. GO! gets User defined methods
- 10. Methods Some fancy string methods .reverse .upcase .downcase .swapcase .capitalize .center (width) .ljust width .rjust width
- 11. Methods Some number methods ** #exponential % #modular .abs #absolute value rand(number) #generate a random number srand(seed) #generate a random seed
- 12. Methods More on user defined methods, similar to Python! def functionName (arg1, arg2) #do something return ret_val end Actually we don’t have to return because…. Case1: the function doesn’t have to return Case2: the last line is the default return value
- 13. Flow Control Conditional flow control Looping flow control if condition1 while condition #do something #do something elsif condition2 end #do something else #do something end Don’t forget end
- 14. The End The first part is over, please wait for the second part Any comments would be appreciated Welcome to my study page http://bradyisstudying.blogspot.tw/