Ruby/Array/uniq

shopping_list = %w[ cheese bread crackers potatoes carrots cheese ]
shopping_list.uniq! # => ["cheese", "bread", "crackers", "potatoes", "carrots"]

survey_results = [1, 2, 7, 1, 1, 5, 2, 5, 1]
p distinct_answers = survey_results.uniq           # => [1, 2, 7, 5]
p survey_results.uniq!
p survey_results                                   # => [1, 2, 7, 5]

# uniq method removes duplicates from a single array, creating a new array. 
# uniq! changes the array itself, in place.
 
shopping_list = %w[ cheese bread crackers potatoes carrots cheese ]
# => ["cheese", "bread", "crackers", "potatoes", "carrots", "cheese"]
shopping_list.uniq!=> ["cheese", "bread", "crackers", "potatoes", "carrots"]