methods.rb

require "date"

def greetings(name)
  "Welcome to London #{name}! I hope you enjoy it!"
end

# puts greetings("James")
# puts greetings("Nathan")

# def one_plus_one
#   1 + 1
# end

# puts one_plus_one

# def double(number)
#   2 * number
# end

# puts double(20)

# def multiply(first_number, second_number)
#   first_number * second_number
# end

# puts multiply(3, 10)

# def nice_name(first_name, last_name)
#   name = "#{first_name.upcase} #{last_name.capitalize}"

#   return name
# end

# puts nice_name("Alex", "hauMer")
# puts nice_name("Ed", "Melech")

# def tomorrow
#   tomorrow_date = Date.today + 1
#   return tomorrow_date.strftime("%B %d")
# end

# puts tomorrow

recap.rb

# Stings
"Hello Batch 523"
"1985".to_i

# Integers
1
2 + 5
4 * 2
10.to_s
10.to_f

# Floats
1.0
2.0 + 5.0
4.0 * 2.0
7.0 / 2.0 # yields a result with decimal places

# Arrays
[]
[1, 2, 3]
["Hello", "batch", "523"]
["Hello", 2, true] # mixed array
["London", "birmingham", "manchester"]
    # 0            1             2

# Booleans
true
false
nil

# Range
(1..10).to_a # creates an array form 1 to 10
(1...10).to_a # excludes upper bound

# -------------------------------------------

# Concatenation
age = 23
"I am" + " " + age.to_s + " " + "years old"

# Interpolation
"I am #{age} years old!" # needs double quotes
"I am #{20 * 8} years old!"

vars.rb

# age = 99

# puts "Hello, I am #{age} years old!"

# puts "Next year I will be #{age + 1} years old!"

# we_typically_use_snake_case # varibale syntax

city = "London"
population = 7000000
mayor = "Sadiq Khan"

puts "The city of #{city} has a population of #{population} and the mayor is #{mayor}!"

mayor = "Boris Johnson"
puts "In the past #{city} had a population of #{population / 2} and the mayor was #{mayor}"
puts population

population = population + 1
# population += 1 # shortcut for above

puts population

population = population - 10
# population -= 10 # shortcut for above

puts population

# cmd + /
# cmd + d
# cmd + shift + d