Week 1 Notes

week-1/basics.rb

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+=begin
+
+R U B Y ♦️
+
+- Ruby is a dynamic, interpreted, object-oriented, high-level programming language that was created for developer happinness and was created in 1995 to emphasize the needs of humans over computer. 
+This makes the language reads like almost english. 
+- Interpreted means that you do not need a compiler to write or run Ruby, you can write it in your terminal and it will run.
+- Ruby is case sensitive and cares about capitalizations 
+- to print variables with Ruby you use "puts" or "print" commands; the puts command adds a new line after the output, while the print command does not
+- Single line comments are written with a hashtag (#) and multiline comments are written with =begin and =end
+
+D A T A  T Y P E S  &  V A R I A B L E S 
+
+- Numeric (integers, floats)
+- Strings (text in strings)
+- Booleans (true/false)
+- Arrays (lists)
+- Hashes (key/value pairs)
+- Symbols (immutable strings)
+- nil (nothingness)
+
+To write variables in Ruby, you need to use snake_case.
+Eg: my_variable = 5
+
+
+A R I T H M E T I C  O P E R A T O R S 
+
+- Addition (+)
+- Subtraction (-)
+- Multiplication (*)
+- Division (/)
+- Exponentiation (**) - raises a number to the power of another number
+- Modulo (%) - returns the remainder of a division
+
+EVERYTHING IN RUBY IS AN OBJECT 
+
+- Ruby has built-in methods that can be called on objects
+- Methods are called by appending the object with a dot (.) and the method name
+- Methods can take arguments, which are passed in parentheses after the method name
+- Methods can be chained together to do more complex operations
+    Eg: "hello".capitalize.reverse 
+- Methods can have an exclamation mark (!) at the end of their name to indicate that they modify the object they are called on
+    Eg: name = "ruby" 
+        name.capitalize! 
+        puts name 
+        => Ruby 
+
+- String Methods: 
+    - .length : returns the length of a string
+    - .strip : returns a copy of the string with whitespace removed from the beginning and end
+    - .split : returns an array of substrings separated by a delimiter
+    - .start_with? : returns true if the string starts with one of the prefixes given
+    - .first : returns the first element of an array
+    - .last : returns the last element of an array
+    - .upcase : returns a copy of the string converted to uppercase
+    - .downcase : returns a copy of the string converted to lowercase
+    - .capitalize : returns a copy of the string with the first character converted to uppercase and the remainder to lowercase 
+    - .reverse : returns a copy of the string with the characters in reverse order
+    - .include? : returns true if the string contains the given substring or character
+    - .empty? : returns true if the string is empty 
+    - .nil? : returns true if the string is nil 
+    - .index : returns the index of the first occurrence of the given substring or character
+
+    To print a string with a variable, you can use string interpolation:
+    Eg: name = "ruby"
+        puts "Hello #{name}!"
+        => Hello ruby!
+
+    ll stings start at  index 0, and you can access individual characters using bracket notation:
+    Eg: name = "ruby"
+        puts name[0]
+        => r
+
+    Ruby String methods cheatsheet: https://www.shortcutfoo.com/app/dojos/ruby-strings/cheatsheet
+
+
+- Numeric Methods:
+    - .odd? : returns true if the number is odd
+    - .even? : returns true if the number is even
+    - .round : rounds a float to the nearest integer
+    - .abs : returns the absolute value of a number
+    - .times : iterates block int times, passing in values from zero to int - 1
+    - .upto : iterates block int times, passing in values from zero to int - 1
+    - .floor : returns the largest integer less than or equal to float
+    - .ceil : returns the smallest integer greater than or equal to float
+    - .to_i : converts a number to an integer
+    - .to_f : converts a number to a float
+    - .to_s : converts a number to a string
+
+    Numeric Class
+    - Math is a module that provides a lot of mathematical methods and constants. For example Math.log(1) => 0.0
+    - there are a lot of math operations in the Math module/class
+
+    When you add two integers you get an interget; when you add an integer and a float you get a float; when you add two floats you get a float.
+    Ruby distinguishes between integers and floats, and will convert between them as needed.
+
+    More number methods: https://www.freecodecamp.org/news/ruby-number-methods-integer-and-float-methods-with-examples/ 
+
+- Getting input from users: 
+    - gets is the Ruby method that retrieves input from users. 
+    - "chomp" removes the extra line that is automatically added by the gets method 
+    - gets.chomp : gets input from users and stores it in a variable 
+
+
+=end 
+
+# Nums Boolean and String examples 
+my_num = 25
+my_int = 25.7
+my_boolean = true
+my_string = "Ruby"
+
+puts my_num
+puts my_boolean
+puts my_string
+
+# Arithmetic Operators examples
+
+puts 5 + 5
+puts 5 - 5
+puts 5 * 5
+puts 5 / 5
+puts 5 ** 5
+puts 5 % 5
+
+# String Methods examples
+
+puts "hello".capitalize
+puts "hello".reverse
+puts "hello".upcase
+puts "hello".downcase
+puts "hello".length
+puts "hello".include?("h")
+puts "hello".include?("z")
+puts "hello".empty?
+puts "hello".nil?
+puts "hello".split
+puts "hello".start_with?("h")
+puts "hello".start_with?("z")
+puts "hello".first
+puts "hello".last
+puts "hello".strip
+puts name = "Hello".downcase.reverse.upcase #chaining methods
+
+# Numeric Methods examples
+
+puts 5.odd?
+puts 5.even?
+puts 5.round
+puts 5.abs
+puts 5.times
+puts 5.upto
+puts 5.floor
+puts 5.ceil
+puts 5.to_i
+puts 5.to_f
+
+# Gettiing input from users
+
+puts "What is your name?"
+name = gets.chomp # use gets.chomp to get input from users + store in a var
+puts "Hello #{name}!"
+
+# modifying original var/object with !
+print "What city are you from?"
+city = gets.chomp
+city.capitalize!
+puts "You are from #{city}!"
+
+

week-1/calculator.rb

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+=begin 
+- To build a calculator we need to get input from the user,
+- the inputs will be numbers and the operations to perform on those numbers 
+- perform some operations on the input and then output the result to the user 
+- we will use the gets method to get input from the user
+- we will use the chomp method to remove the newline character from the input
+- we will use the to_i method to convert the input to an integer
+- we will use the puts method to output the result to the user
+- be sure to handle float inputs as well as integer inputs
+
+=end 
+
+# simple calculator to add 2 numbers 
+print "Enter a number: "
+num1 = gets.chomp().to_i
+print "Enter another number:"
+num2 = gets.chomp().to_i
+
+print (num1 + num2)
+
+# create a more complex calculator that asks a user what operation they want to do with the numbers and do that operation with the numbers.
+# is the user enters a word to represent the operation, we will need to convert that word to a symbol
+

week-1/control_flow.rb

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+=begin
+
+C O N T R O L  F L O W
+
+
+
+
+
+=end

week-1/installation.rb

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+=begin
+
+I N S T A L L A T I O N
+
+If you have a Mac, Ruby is automagically installed on your machine. Open your terminal and run the following command to check which version of Ruby you have installed:
+`ruby -v` this should output the version of Ruby that you have. 
+
+If you have a Windows machine, you can download Ruby from here: https://rubyinstaller.org/downloads/ and follow the instructions in this freecodecamp ruby video
+- installation starts at  (1:24) Windows Installation
+- https://www.youtube.com/watch?v=t_ispmWmdjY&t=4095s 
+
+
+You may also want to install a Ruby Version Manager (RVM) to manage multiple versions of Ruby on your machine.
+- I used this tutorial: https://nrogap.medium.com/install-rvm-in-macos-step-by-step-d3b3c236953b
+
+
+For this course, you will need to have a Code Editor installed on your machine. I recommend using Visual Studio Code (VSCode) which you can download here: https://code.visualstudio.com/download
+- With VS Code you can run ruby code directly in the editor, which is very convenient.
+- I recommend adding the following extensions to your VS Code:
+    - Ruby https://marketplace.visualstudio.com/items?itemName=rebornix.Ruby
+    - VSCode Ruby https://marketplace.visualstudio.com/items?itemName=wingrunr21.vscode-ruby This extension will be installed automagically when you install the Ruby extension
+
+Running Ruby Code in VS Code
+
+- To run Ruby code in VSCode, open up a new file and save it with the .rb extension.
+- To run the code, you can open up a new terminal in VSCode and run the following command:
+    - `ruby <filename>.rb`
+- You can also run the code directly in the editor by pressing the play button in the top right corner of the editor window.
+
+=end
+
+# Example of Ruby Code
+puts "Hello World!"

week-1/madlibs.rb

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+=begin
+Madlibs game is one where you ask the user for input, and then you plug that input into a story that you create.
+=end
+
+# Simple Madlibs Game
+puts "Enter a color: "  
+color = gets.chomp()
+puts "Enter a plural noun: "
+plural_noun = gets.chomp()
+puts "Enter a celebrity: "
+celebrity = gets.chomp()
+puts "Enter a verb: "
+verb = gets.chomp()
+
+puts ("Roses are " + color)
+puts (plural_noun + " are blue")
+puts ("I love " + celebrity)
+puts ("So " + verb + " you are cool")