Add info about sets

Python/019_datastructures.py

@@ -1,5 +1,6 @@
 # Data Structures
 #   Data structures hold sets of data in various formats
+#   We will discuss: list, dictionary (dict), tuple, set
 
 # List
 # Lists have collections of data
@@ -73,4 +74,27 @@ print(f"Color tuple: R={color[0]} G={color[1]} B={color[2]}")
 #    strings: "Cheese"
 #    integers: 44
 #    lists: ['a', 'b', 'c']
-#    objects: MyClass(param1, param2)
+#    objects: MyClass(param1, param2)
+
+# Set
+# Sets have collections of data
+# set elements must be unique in the set
+# Usually of the same type because uniqueness makes less sense otherwise
+# with elements separated by commas
+# where elements are unordered (i.e. can't reference specific element, slice, or index)
+# are contained within curly braces
+# Note: Once a set has been created its values cannot be changed,
+#       and elements cannot be added/removed
+
+# Declare our set
+dice = {"1", "2", "3", "4", "5", "6"}
+# Testing if an element exists is done with "in"
+if "3" in dice:
+    print("The dice set contains a 3!")
+# Iterate over a set
+for die in dice:
+    print(f"dice element: {die}")
+# NOTE!! You will see that the printed elements are in an arbitrary order.
+#        Because sets are unordered you cannot rely on which element comes
+#        before or after another element and will likely not match the order
+#        created inside the set declaration.