Sets and tuples

Introduction to Python for Developers

George Boorman

Curriculum Manager, DataCamp

Sets

Contain unique data
Unchangeable*
- Can add or remove values, but cannot change them
Ideal to identify and remove duplicates
Quick to search (compared to other data structures such as lists)

Creating a set

Set = {}
: = Dictionary
No : = Set

# Create an attendee set
attendees_set = {"John Smith", "Alan Jones", "Roger Thompson",
                 "John Smith", "Brandon Sharp", "Sam Washington"}
print(attendees_set)

{'Alan Jones', 'Brandon Sharp', 'John Smith',
 'Roger Thompson', 'Sam Washington'}

Converting to a set

# Existing list variable
attendees_list = ["John Smith", "Alan Jones", "Roger Thompson",
                  "John Smith", "Brandon Sharp", "Sam Washington"]


# Convert to a set
attendees_set = set(attendees_list)


# Check the data type
type(attendees_set)

set

Converting to a set

print(attendees_set)

{'Sam Washington', 'Roger Thompson', 'Alan Jones', 'John Smith', 'Brandon Sharp'}

Limitations of sets

Don't have an index
- Can't have duplicates
- Can't subset with []

# Trying to subset a set
attendees_set[0]

TypeError: 'set' object is not subscriptable

Sorting a set

attendees_set = {"John Smith", "Alan Jones", "Roger Thompson",
                 "John Smith", "Brandon Sharp", "Sam Washington"}


# Sorting a set
sorted(attendees_set)

['Alan Jones', 'Brandon Sharp', 'John Smith', 'Roger Thompson', 'Sam Washington']

sorted() returns a list

Tuples

Immutable - cannot be changed
- No adding values
- No removing values
- No changing values

Ordered
- Can subset by index i.e., [0]

Padlock on top of a laptop

¹ https://unsplash.com/@towfiqu999999

Creating a tuple

# Creating a tuple
office_locations = ("New York City", "London", "Leuven")


# Convert another data structure to a tuple
attendees = tuple(attendees_list)

Accessing tuples

# Access the second element
office_locations[1]

"London"

Data structures summary

Data structure	Syntax	Immutable	Allow duplicate values	Ordered	Subset with `[]`
List	`[1, 2, 3]`	No	Yes	Yes	Yes - index
Dictionary	`{key:value}`	No	Yes	Yes	Yes - key
Set	`{1, 2, 3}`	No	No	No	No
Tuple	`(1, 2, 3)`	Yes	Yes	Yes	Yes - index

Let's practice!

Introduction to Python for Developers