Learn
Sets
Review

Great job completing this lesson!

Let’s go over what we learned:

  • A set is an unordered collection of unique elements.

  • We have the option to initialize sets that are either empty or populated:

    var emptySet = Set<Type>() var populatedSet: Set = [Value1, Value2, Value3]
  • To add new elements to a set, use the built-in method, .insert(Value).

  • We can remove a single element from a set using .remove(Value) or we can remove all the values from a set with .removeAll():

  • If we want to check if a value exists within a set, we can use the method .contains(Value) .

  • A for-in loop can be used to iterate through all the values of a set:

    for placeholder in setName { // Body of loop }
  • We can use set operations to modify or create new sets based on the data in two different sets.

  • The .intersection() operation creates sets with values that overlap in two sets:

    soda.intersection(seltzer)
  • The .union() operation combines all the values of two different sets:

    ketchup.union(mayo)
  • The operation .symmetricDifference() creates a set of items that appear in one set, but not both:

    capulets.symmetricDifference(montagues)
  • .subtracting() is a set operation that removes the overlapping data of one set from another:

    milkshake.subtracting(iceCream)

Instructions

Feel free to use the space in Review.swift to practice using sets.

When you’re ready to move on, click Up Next.

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