101-01.txt

In Ruby, your information (or data) can come in different types.
Let's learn about three to start: numbers, booleans, and strings.

Let's set a variable `my_num` to the value 25
my_num = 25

Let's set a variable `my_boolean` to the value true
my_boolean = true

Set `my_string` to "Ruby"
my_string = "Ruby"

One of the most basic concepts of programming is the variable.
You can think of a variable as a name for a value.
They're called variables because their values can vary. :)

my_num = 25
my_num = 30
my_num

Math
2 * 3
10 + 5
100 / 10
10 ** 10 <-- Exponentiation, raising a number to a power
4 % 2 <-- Modulo, returns the remainder of division

puts and print
The print command take whatever you give it and prints it to the screen.
puts (for put string) is slightly different. It adds a new blank line after the
thing you want to print.

puts "What's up?"
print "Sup yo"

String Methods

Everything in Ruby has certain built-in abilities called methods.
You can think of methods as "skills" that certain things have.
For instance, strings (words or phrases) have built-in methods
that can tell you the length of the string, reverse the string,
and more.

"I love gin so much".length
"Bryan Woods".length
"Bryan".reverse
"bryan".upcase
"BRYAN".downcase
"Bryan".upcase.downcase

String Concatenation
"Bryan " + "Woods"

String interpolation
"Hi my name is #{name}"

Comments
# I am a full line comment!
"Bryan".length # I'm a comment too!

Naming Conventions
Local variables
Lowercase, snake case

my_name = "Bryan"

Exercise!
Create a variable called my_name and set it equal to your name as a string.
Create a variable called my_age and set it equal to your age as a number.

Math
Create a variable called sum that is equal to 13 + 379
Create a variable called product that is equal to 923 * 15
Create a variable called quotient that is equal to 13209 / 17

Declare a variable name and set it equal to a string containing your name.
Call .downcase on your name to make it all lowercase, call .reverse on your
lowercase name to make it backwards, then call .upcase on your backwards name
to make it ALL CAPS.

You can do this in two ways. Each method call on a separate line, or you can
chain them together.
name.method1.method2.method3


Take home assignment:

1. Write a program that prints the sum of the following two numbers:
30 to the power of four and 40 times eight.

2. Write a program that stores your name, age, and city in variables with those
names, and then prints an excited introduction with your name in all caps,
your age, your city in all caps, and ends with an exclamation point.

So for instance my program would set name to "Bryan Woods", age to 29, and
city to "Brooklyn" and print the following string:

"My name is BRYAN WOODS, I'm 29 years old, and live in BROOKLYN!"

3. Here is a link to the Ruby documentation for strings:
http://www.ruby-doc.org/core-2.1.1/String.html#method-i-5B-5D

Let's say I've go the string "Hello!" but have decided that it seems too exciting.
I want to chop off the last character at the end of the string.
Can you find a method that allows you to do this?

Ie: "Hello!".thismethod
should return "Hello"
Or "Kennethh".thismethod
should return "Kenneth"

examples.rb

# irb...
# Numbers
3 + 2

# Strings
puts "Hi, everybody!"

# Booleans
true
false
nil

# Variables
x = 100
puts x

# Math
# Addition (+)
# Subtraction (-)
# Multiplication (*)
# Division (/)
# Exponentiation (**) (raises one number to the power of the other)
# Modulo (%) (returns the remainder after division)
1 + 2
3 - 5
3 * 3
9 / 3
3 ** 2
21 % 7

# Puts and print
puts "Yo what's your name?"
print "Um...Bryan"

# Methods
"I love gin...gin gin gin".length
# You call methods with a `.`.
# `length` is a method all strings in Ruby have. It returns the string's
# length.
"Bryan".length

"Bryan".reverse

puts "bryan".upcase
puts "BRYAN".downcase

# Comments
# I'm a comment
3 + 2 # 5!!

# Local variables are lowercase and snakecase
name = "Bryan"
puts "Hi my name is #{name}"

my_name = "Bryan"
my_age = 29