Array methods

array_methods.rb

# Array definition

def new_array(a,b,c,d)
  [a,b,c,d]
  # or:
  # Array.new << a << b << c << d
  # but you would never do that...
end

def first_and_last(a)
  [a.first,a.last]
  # another way:
  # [] << a.first << a.last
  # or:
  # Array.new << a.first << a.last
end

def no_fruits?(a)
  a.length == 0  # or a.empty?
end

# Array Methods

def reverse_plus_one!(a)
  a << a.first
  a.reverse!
end

def pluses_everywhere(a)
  a.join("+")
end

def array_quantity_plus_one(a)
  a.length + 1
end

# Grocery List

def add_item!(item, list)
  list << item unless list.include?(item)
  list # must return list since if list includes item, the previous line evaluates to nil
end

def remove_item!(item, list)
  list.delete(item) if list.include?(item)
  list # must return list since Array#delete returns the item that is deleted
end

def show_list(list)
  list.sort.uniq
end