Functions

• just like a VARIABLE is a name for a chunk of data
• a FUNCTION is a name for a chunk of code
• if you have some code you want to run again and again
  • or just run once, but keep it organized

For example

Here's a not very useful function:

def add x, y
  x + y
end

• def means "define a function"
• add is the name of the function
• x, y are the parameters of the function
• x + y is the body of the function
  • also the return value

Call Me, Maybe

You call a function by its name

def add x, y
  x + y
end

add 2, 3  # returns 5

add 12, 30  # returns 42

Rant!!!

def rant s
  s.upcase.gsub(" ", "") + "!!!"
end

puts rant "i like pizza"

Capitalize Just The First Character

def initial_cap s
  s[0] + s[1,s.length].downcase
end

puts initial_cap("McElaney")

this program prints Mcelaney

Titleize

def titleize string
  string.split(' ').map(&:capitalize).join(' ')
end

• The funny &: means "send this message"
• map(&:capitalize) means "send the message capitalize to every item in the array"