Data Science Portfolio

Sets

Basics

• A set is an unordered collection with no duplicate elements
• Uses: membership testing, eliminating duplicate entries
• A set can be initialized using curly braces or the set() function
  • Duplicate values will automatically be filtered out
• Note: to create an empty set, use set() as opposed to {}
  • {} will create an empty dictionary instead

Create a set using curly braces

pets = {'dog', 'cat', 'parrot', 'cat', 'dog', 'rabbit', 'hamster', 'dog'}

# Confirm that duplicates are removed
print(pets)

{'parrot', 'hamster', 'dog', 'cat', 'rabbit'}

Set Operations

Create sets from two words

a = set('calcariferous')
b = set('demagogue')

Unique letters in a

a

{'a', 'c', 'e', 'f', 'i', 'l', 'o', 'r', 's', 'u'}

Unique letters in b

b

{'a', 'd', 'e', 'g', 'm', 'o', 'u'}

Letters in a but not in b

a - b

{'c', 'f', 'i', 'l', 'r', 's'}

Letters in a or b or both

a | b

{'a', 'c', 'd', 'e', 'f', 'g', 'i', 'l', 'm', 'o', 'r', 's', 'u'}

Letters in both a and b

a & b

{'a', 'e', 'o', 'u'}

Letters in a or b but not both

a ^ b

{'c', 'd', 'f', 'g', 'i', 'l', 'm', 'r', 's'}