Crypto-Tech

Ruby 03: Comments, Variables, Code Formatting
Best way to learn basic programming skills!

Basic Ruby Tutorials: 01 | 02 | 03 | 04 |

Single Line Comment, Initialize a Variable, Simple Character Formatting, Simple User Input, Simple Hash

Instructions: open this text file and a.) copy and paste code into the Atom.io code editor and save as test3.rb, or b.) copy and paste code into a TextEdit file in your learnRuby directory and save as test3.rb - remember to select Format => Make Plain Text. Or you can copy and paste into your Ruby file using the code below.

1.) Single Line Comment, Initialize a Variable, Simple Character Formatting

Code section below is stand-alone.

Copy and paste this code into a new .rb file:
# START COPY AND PASTE HERE: RUBY code example
# each section below can be run by itself
# SECTION 1 Comments and character formatting
# single-line comments start with the pound sign # # everything in this line is ignored. no code in this line is processed
# each line usually has one statement (or condensed statement)
# no semicolon is needed at end of a line
# for 2 ruby statements on one line ; separate them with a semi-colon like this line
# brackets { } enclose Ruby formulas, methods, series of commands or data

# Initialize a variable = name a variable and set initial value
myFirstName = hermione # initialize var
myLastName = granger # initialize var
puts myFirstName.capitalize # print var and capitalize
puts myLastName.upcase # print var and upper case
puts myLastName.length # print var length
puts # prints empty line for code readability
puts
# end section 1
# END COPY AND PASTE HERE


Do not copy this part. Note: Each section contains stand-alone code. After copying and pasting the code above, you have the option to save and run the new Ruby .rb code above in a command terminal window using the step 5 instructions. Then keep on adding code for each section below and running the file.

2.) Simple User Input gets.chomp

Code section below is stand-alone.

Copy and paste this code under code above:
# START COPY AND PASTE HERE
# SECTION 2 Simple User Input
puts USER INPUT
# USER INPUT syntax-format: gets.chomp.nextParameter
# print same as puts except no carriage return (no new line)
print Please enter your first name:
userInput = gets.chomp.capitalize; # initialize user input var

print Please enter your last name: ;
lastName = gets.chomp.capitalize # initialize user input var

puts Your name is #{userInput} #{lastName}!; # print to screen
puts # prints empty line for code readability
puts
# end section 2
# END COPY AND PASTE HERE

3.) Simple Hash Using Colon : Syntax

How to initialize a simple hash map (data lookup structure) with keys and values using the colon : syntax. A Ruby hash index is created with arbitrary keys of any object type. The hash order is by either key or value, typically not input order.

Code section below is stand-alone.

Copy and paste this code under code above:
# START COPY AND PASTE HERE
# SECTION 3 Initialize hash map
# initialize a simple hash map (lookup structure) with keys and values
# hash is typically good for random data. hash does not categorize-assign items with an index number
# hash can be easily converted to array (with zero number indexing format)
# hash is created with arbitrary keys of any object type, alphabetic, number, symbol
# hash order is by either key or value, typically not input order
# ========================
# hash initialization and item entry are all condensed into one line/unit below
# initialize fruits hash using following syntax: hashName = { }
# specify hash items using colon syntax, key : value
# mango is a key, 26 is a value
fruits = { mango: 26, kiwi: 48, coconut: 9 }
# print all fruits keys and values to terminal
puts ALL FRUITS KEYS (Names) # prints title
puts fruits.keys # print all hash keys
puts ALL FRUITS VALUES (Amounts)
puts fruits.values # print all hash values

# add new item to fruits hash
# add pineapple as key and 17 as value
# syntax is hashName[:key] = value
fruits[:pineapple] = 17
puts ALL FRUITS KEYS ADD PINEAPPLE (Names)
puts fruits.keys
puts ALL FRUITS VALUES ADD PINEAPPLE (Amounts)
puts fruits.values
puts # prints empty line for code readability
puts
# end section 3
# END COPY AND PASTE HERE

4.) Simple Hash Using Hash-Rocket => Syntax

Copy and paste this code under code above:
# START COPY AND PASTE HERE
# SECTION 4 Initialize hash map with => syntax
# initialize hash using following syntax: hashName = { }
# initialize hash items using hash-rocket => syntax, food1 => chlorella
# food1 is a key, chlorella is a value
superfoods = {
food1 => chlorella, # Add items with => syntax
food2 => nori,
food3 => bee pollen,
food4 => sauerkraut,
food5 => kimchi
}

puts SUPERFOODS HASH food3 IS: # print title
puts superfoods[food3]; # print value for key food3
puts ALL SUPERFOODS KEYS # print title
puts superfoods.keys # print all hash keys
puts ALL SUPERFOODS VALUES
puts superfoods.values # print all hash values
puts # prints empty line for code readability
puts
# end section 4
# END COPY AND PASTE HERE

5.) Run the test3.rb File

Run the test3.rb file in the command window just as in tutorial 1: