Python Sets
New Courses Coming Soon
Join the waiting lists
Sets are another important Python data structure.
We can say they work like tuples, but they are not ordered, and they are mutable. Or we can say they work like dictionaries, but they don’t have keys.
They also have an immutable version, called frozenset
.
You can create a set using this syntax:
names = {"Roger", "Syd"}
Sets work well when you think about them as mathematical sets.
You can intersect two sets:
set1 = {"Roger", "Syd"}
set2 = {"Roger"}
intersect = set1 & set2 #{'Roger'}
You can create a union of two sets:
set1 = {"Roger", "Syd"}
set2 = {"Luna"}
union = set1 | set2
#{'Syd', 'Luna', 'Roger'}
You can get the difference between two sets:
set1 = {"Roger", "Syd"}
set2 = {"Roger"}
difference = set1 - set2 #{'Syd'}
You can check if a set is a superset of another (and of course if a set is a subset of another)
set1 = {"Roger", "Syd"}
set2 = {"Roger"}
isSuperset = set1 > set2 # True
You can count the items in a set with the len()
global function:
names = {"Roger", "Syd"}
len(names) # 2
You can get a list from the items in a set by passing the set to the list()
constructor:
names = {"Roger", "Syd"}
list(names) #['Syd', 'Roger']
You can check if an item is contained into a set with the in
operator:
print("Roger" in names) # True
Here is how can I help you:
- COURSES where I teach everything I know
- CODING BOOTCAMP cohort course - next edition in 2025
- THE VALLEY OF CODE your web development manual
- BOOKS 16 coding ebooks you can download for free on JS Python C PHP and lots more
- Interesting links collection
- Follow me on X