IT 231

Spring 2018

Craig Miller

• Home
• Basic Information
• Grades and Policies
• Schedule

Weekly Notes

• Week 1
• Week 2
• Week 3
• Week 4
• Week 5
• Week 6
• Week 7
• Week 8
• Week 9
• Week 10

Assignments

• Assignment 1
• Assignment 2
• Assignment 3
• Assignment 4
• Assignment 5
• Assignment 6

Technical References

• Ruby on Rails Documentation
• Mozilla Technical Documents
• HTML Tag Reference
• CSS Property Reference
• JavaScript Guide

Ruby List Tutorial

This tutorial reviews some basic statements for interacting with lists (also called arrays) using Ruby. To run these statements, you will to first open a Ruby console window.

Try out each of the commands. As much as possible, try to predict what each statement will do before you press Enter.

1. animals = ["cat", "dog", "pig", "cow"]
2. animals
3. animals.length
4. animals.include?("pig")
5. animals.include? "pig"
6. animals[3]
7. animals[3].upcase
8. animals.each { |x| puts x }
9. animals.each { |x| puts x.length }

Finally, put the following lines in the file mylists.rb:

farm_animals = ["cat", "dog", "horse", "cow"]
farm_animals.each do |animal|
	if animal == "cow"
		puts "MOOO!"
	else
		puts "???"
	end
end

At a command console type: ruby mylists.rb (make sure that this file is in the same folder as the command console.

Or, with the interactive ruby interpreter, type: load mylists.rb (again making sure that the current folder has this file.

Modify the file so that it shows different outputs