Sets
You will learn about the set object in Python in this lesson.
Definition
A set is a collection of values that are not necessarily all the same type. To write a set, use braces around a comma-separated list. Take a look at a few examples using sets below:
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int_set = {1, 2, 3, 4, 5} # set having all integer valuesprint(int_set)s = {10, "ten", "X"} # set having mixed data typesprint(s)
Empty set
In Python, an empty set (one with no elements) cannot be written as {}
. Instead, the set()
function is used.
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emp_dict = {} # creating empty dictionaryemp_set = set() # creating empty set# checking data types of both variablesprint("Type of emp_dict:", type(emp_dict))print("Type of emp_set:", type(emp_set))
Set properties
Sets have two important properties:
- Sets have no duplicate elements. A value is either in the set, or it is not in the set. Sets provide the
in
andnot in
operators which allow us to check duplicates.
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s = {10, "ten", "X", "X"} # A set having mixed data type valuesprint(s) # this will give (10, "ten", "X") since sets have no duplicate elementsprint("In:", 10 in s) # checking if 10 is present in s -> Trueprint("Not in:", "TEN" not in s) # checking if TEN is not present in s -> True
- The order of elements in a set is unspecified, so you cannot index