Collections
List
Lists can be created using list() or [].
cities = list('Madrid', 'Tokyo')
cities = ['Madrid', 'Tokyo']
Some common operations:
numbers = [1, 2, 3]
numbers[0] # Access by index
numbers.append(4) # Add an element
numbers.remove(2) # Remove an element
numbers.sort() # Sort the list
numbers.reverse() # Reverse the list
numbers[1:3] # Slice the list
Tuple
Tuples can be created using tuple(), () or several values separated by comma.
numbers = tuple([1, 2, 3])
numbers = (1, 2, 3)
numbers = 1, 2, 3
You can access elements by index or slice them, but tuples are immutable, so their values can't be changed.
coordinates = (10, 20)
coordinates[0] # Access by index
coordinates[1:] # Slice the tuple
Set
Sets can be created with set() or {}.
fruit = set(['apple', 'banana', 'pineapple'])
fruit = {'apple', 'banana', 'pineapple'}
Some common operations:
unique_numbers = {1, 2, 3}
unique_numbers.add(4) # Add an element
unique_numbers.remove(1) # Remove an element
set1 = {1, 2}
set2 = {2, 3}
set1 | set2 # Union
set1 & set2 # Intersection
set1 - set2 # Difference
Operation | Equivalent | Result |
|---|
a.issubset(b)
| a <= b
| Checks if a is inside b |
a.issuperset(b)
| a >= b
| Checks if b is inside a |
a.union(b)
| a \| b
| New set with the elements of both |
a.intersection(b)
| a & b
| New set with the elements common to both |
a.difference(b)
| a - b
| New set with elements in a but not in b |
a.symmetric_difference(b)
| a ^ b
| New set with elements in either a or b but not both |
Dictionary
Dictionaries are created with dict() or {key: value}.
score = dict('dani' : 6, 'fanta' : 5)
score = {'dani' : 6, 'fanta' : 5}
Dictionaries are the same as a JSON in JS or a Map in Java.
Some common operations:
person = {'name': 'Daniel', 'age': 24}
person['name'] # Access value by key
person.get('name') # Access value by key safely
person.get('name', 'None') # Access value by key safely, default if missing
person['age'] = 26 # Update value
del person['name'] # Delete a key-value pair
person.keys() # Get all keys
person.values() # Get all values
person.items() # Get all pairs of keys values
Last modified: 17 March 2025