Sets in Python are equivalent to sets in Mathematics. They look similar to lists, however they have a much different use. Every element in a set must be unique. If an element is added to it when it already exists, then no new element will be added.
A set is an unordered collection of unique elements; any duplicates are automatically removed upon creation or insertion.
Sets are written with curly brackets {},
or the built in function set.
Sets A through C make singular value sets, while D
makes a set of 3 elements. Similar to
the tuple function, using the set function
requires a comma in the special case of a single element in the set.
Unlike with lists or tuples, duplicates are automatically removed. Additionally, the order doesn't matter. In the third print statement we include a Boolean expression which we will learn in the Operators with Booleans lesson.
Once a set is created, we can continue adding elements to it or remove
elements from it. We use the methods add
and remove respectively.
Sets can even have different datatypes, such as tuples. Though mixing datatypes like this is discouraged.
We can test if something is in a set using the statement in.
This will return a Boolean value True or False.
The latter two print statements show the difference between identifying an integer and a tuple.
Considering that sets only keep the unique values, what will the set below be reduced to?
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