Lists, Tuples, Sets & Dictionaries
Lists are ordered, mutable collections in square brackets []. Methods: append, extend, insert, remove, pop, sort.
Python Lists
Lists are ordered, mutable collections in square brackets []. Methods: append, extend, insert, remove, pop, sort.
Lists can hold mixed types and are the default dynamic array in Python.
Real-life example: A list is a shopping list — you can add, remove, and reorder items anytime.
skills = ["python", "sql"]
skills.append("git")
skills[0] = "Python"
print(skills, len(skills))Python Tuples
Tuples use parentheses () and are ordered but immutable — good for fixed records like coordinates.
Unpacking lets you assign multiple variables at once.
Real-life example: A tuple is a sealed exam paper — you can read it but not erase answers.
point = (10, 20)
x, y = point
print(x, y)Python Sets
Sets store unique unordered items in curly braces {}. Great for removing duplicates and membership tests.
Set operations include union (|), intersection (&), and difference (-).
Real-life example: A set is a bag of unique marbles — duplicate colors automatically disappear.
tags = {"api", "backend", "api"}
print(tags) # {'api', 'backend'}Python Dictionaries
Dicts map keys to values with {}. Keys must be hashable (usually strings or numbers).
Use .get() for safe access, .keys(), .values(), .items() for loops.
Real-life example: A dictionary is a phone contact book — name (key) points to number (value).
student = {"name": "Riya", "score": 92}
student["score"] = 95
print(student.get("name"), student["score"])