Sets and tuples

Introduction to Python for Developers

Jasmin Ludolf

Senior Data Science Content Developer

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 a set of ingredients
ingredients = {"pasta", "tomatoes", "pasta", 
                 "basil", "garlic", "olive oil", "salt"}
print(ingredients)

{'pasta', 'tomatoes', 'garlic', 'basil', 'olive oil', 'salt'}

Converting to a set

# Existing list variable
ingredients_list = ["pasta", "tomatoes", "garlic", "basil"
                    "olive oil", "pasta", "salt"]


# Convert to a set
unique_ingredients = set(ingredients_list)


# Check the data type
type(unique_ingredients)

set

Converting to a set

print(unique_ingredients)

{'pasta', 'tomatoes', 'garlic', 'basil', 'olive oil'}

Limitations of sets

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

# Trying to subset a set
print(unique_ingredients[0])

TypeError: 'set' object is not subscriptable

Sorting a set

ingredients = {"pasta", "tomatoes", "garlic", 
                 "basil", "olive oil", "salt"}


# Sorting a set
print(sorted(ingredients))

['basil', 'garlic', 'olive oil', 'pasta', 'salt', 'tomatoes']

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]

Useful for location information or identifiers

Padlock on top of a laptop

¹ https://unsplash.com/@towfiqu999999

Creating a tuple

# Creating a tuple
serving_sizes = (1, 2, 4, 6, 8)


# Convert another data structure to a tuple
ingredients_tuple = tuple(ingredients_list)

Accessing tuples

# A tuple
serving_sizes = (1, 2, 4, 6, 8)

# Access the second element
print(serving_size[1])

Let's practice!

Introduction to Python for Developers