Python Cheat Sheet (2026): 250+ Commands with Examples and PDF

What is a Python cheat sheet? A Python cheat sheet is a one-page reference of Python syntax, built-in functions and common methods for strings, lists, tuples, sets, dictionaries and files. This one covers 250+ examples, each with its real output, tested on Python 3.14.

Even experienced developers forget whether sort() returns a value or how negative slicing works. Use this page to look it up in seconds, then get back to coding.

Download the free Python Cheat Sheet PDF (2 pages, printable, updated for 2026)

How to use this page:

• Jump to a section from the table of contents.
• Every row shows the code and what it returns.
• Press Ctrl+F (Cmd+F on Mac) and search for a method name.
• Check your version first: run python –version in a terminal.

Python Basics: Variables, Data Types and Type Conversion

Python is dynamically typed: you create a variable by assigning a value, with no type declaration.

Main Python Data Types

Variables and Basic Syntax

Type Conversion (Casting)

Special Characters (Escape Sequences)

Python Operators Cheat Sheet

Operators work on values. Examples below use a = 10 and b = 3.

Arithmetic Operators

Comparison Operators

Logical, Membership and Identity Operators

Assignment Operators

Bitwise Operators

Operator precedence (high to low): **, then unary -, then * / // %, then + -, then comparisons, then not, and, or. Use parentheses when in doubt.

Python String Methods Cheat Sheet

Strings are immutable: every method returns a new string and leaves the original unchanged.

String Indexing and Slicing

Syntax: s[start:stop:step]. The stop index is excluded. Examples use s = “Python”.

Common String Methods

f-strings and String Formatting

f-strings (Python 3.6+) are the fastest and most readable way to format text. Examples use name = “Asha” and price = 1234.5.

New in Python 3.14: template strings use a t prefix, as in t”Hi {name}”. They return a Template object instead of a str, so libraries can safely process the values (for example, to escape HTML or SQL). For everyday printing, keep using f-strings.

Python List Methods Cheat Sheet

A list is an ordered, mutable collection that allows duplicates. Each example below starts fresh from nums = [3, 1, 4, 1, 5].

List Basics and Slicing

List Methods

List Comprehensions

A list comprehension builds a new list in one line: [expression for item in iterable if condition].

Python Tuple and Set Cheat Sheet

Use a tuple when the data should never change and a set when every item must be unique.

Tuples

Examples use t = (1, 2, 2, 3).

Set Methods

Examples start from a = {1, 2, 3} and b = {3, 4, 5}.

Set Operators (Shorthand)

Python Dictionary Methods Cheat Sheet

A dictionary stores key-value pairs. Keys must be unique and immutable, and since Python 3.7 dictionaries keep insertion order. Each example starts from user = {“name”: “Asha”, “age”: 28}.

Dictionary Basics

Dictionary Methods

Need a real list? Wrap the view: list(user.keys()) returns [‘name’, ‘age’].

Control Flow: if, for, while and match-case

Python uses indentation (4 spaces is the PEP 8 standard) instead of braces to group code blocks.

if / elif / else

marks = 72
if marks >= 90:
    grade = "A"
elif marks >= 60:
    grade = "B"
else:
    grade = "C"
print(grade)   # B

# One-line conditional (ternary)
status = "pass" if marks >= 40 else "fail"   # 'pass'

for Loops

for fruit in ["apple", "mango"]:
    print(fruit)

for i in range(3):           # 0, 1, 2
    print(i)

for i in range(2, 10, 3):    # 2, 5, 8 (start, stop, step)
    print(i)

for index, fruit in enumerate(["apple", "mango"], start=1):
    print(index, fruit)      # 1 apple, 2 mango

for name, score in zip(["Ravi", "Meera"], [82, 95]):
    print(name, score)       # Ravi 82, Meera 95

while Loops, break, continue and else

count = 0
while count < 3:
    count += 1
print(count)   # 3

for n in range(10):
    if n == 2:
        continue   # skip this iteration
    if n == 5:
        break      # exit the loop
    print(n)       # 0, 1, 3, 4

for n in [1, 3, 5]:
    if n % 2 == 0:
        break
else:
    print("No even number found")   # runs only if the loop did not break

match-case (Python 3.10+)

command = "stop"
match command:
    case "start":
        print("Starting")
    case "stop" | "quit":
        print("Stopping")
    case _:
        print("Unknown command")   # default case

Loop Keywords Quick Reference

Python Functions: def, lambda, *args and **kwargs

A function is a reusable block of code defined with def. If it has no return statement, it returns None.

def greet(name, greeting="Hello"):
    """Return a greeting message."""   # docstring
    return f"{greeting}, {name}!"

greet("Asha")                    # 'Hello, Asha!'
greet("Ravi", greeting="Hi")     # 'Hi, Ravi!' (keyword argument)

# Return several values (packed as a tuple)
def min_max(nums):
    return min(nums), max(nums)

low, high = min_max([4, 9, 1])   # low = 1, high = 9

# Type hints (optional, not enforced at runtime)
def add(a: int, b: int) -> int:
    return a + b

*args and **kwargs

def total(*args):            # any number of positional arguments, as a tuple
    return sum(args)

total(1, 2, 3)               # 6

def profile(**kwargs):       # any number of keyword arguments, as a dict
    return kwargs

profile(name="Asha", city="Pune")   # {'name': 'Asha', 'city': 'Pune'}

# Unpack a list or dict into arguments
nums = [1, 2, 3]
total(*nums)                 # 6

Lambda, map, filter and sorted

Scope, Decorators and Generators

count = 0
def increment():
    global count     # modify a global variable
    count += 1

# Decorator: wraps a function to add behaviour
import time
def timer(func):
    def wrapper(*args, **kwargs):
        start = time.perf_counter()
        result = func(*args, **kwargs)
        print(f"{func.__name__} took {time.perf_counter() - start:.4f}s")
        return result
    return wrapper

@timer
def slow_sum(n):
    return sum(range(n))

# Generator: yields values one at a time, saving memory
def countdown(n):
    while n > 0:
        yield n
        n -= 1

list(countdown(3))   # [3, 2, 1]

Python Classes and OOP Cheat Sheet

A class is a blueprint for objects. init runs when an object is created, and self refers to that object.

class Account:
    bank = "TT Bank"                 # class attribute (shared)

    def __init__(self, owner, balance=0):
        self.owner = owner            # instance attributes
        self.balance = balance

    def deposit(self, amount):        # instance method
        self.balance += amount
        return self.balance

    def __str__(self):                # used by print()
        return f"{self.owner}: {self.balance}"

acc = Account("Asha", 500)
acc.deposit(250)    # 750
print(acc)          # Asha: 750

# Inheritance
class SavingsAccount(Account):
    def __init__(self, owner, balance=0, rate=0.04):
        super().__init__(owner, balance)   # call the parent constructor
        self.rate = rate

    def add_interest(self):
        self.balance += self.balance * self.rate

s = SavingsAccount("Ravi", 1000)
s.add_interest()
print(s.balance)                      # 1040.0
print(isinstance(s, Account))         # True

Dataclasses (less boilerplate)

from dataclasses import dataclass

@dataclass
class Product:
    name: str
    price: float
    qty: int = 1

p = Product("Pen", 20.0)
print(p)   # Product(name='Pen', price=20.0, qty=1)

OOP Quick Reference

Exception Handling: try, except, else, finally

try runs risky code, except handles the error, else runs only if no error happened, and finally always runs.

try:
    value = int(input("Enter a number: "))
    result = 100 / value
except ValueError:
    print("That is not a number")
except ZeroDivisionError as err:
    print(f"Error: {err}")           # Error: division by zero
else:
    print(f"Result: {result}")
finally:
    print("Done")                    # always runs

# Catch several exceptions in one line
try:
    risky()
except (KeyError, IndexError) as err:
    print(type(err).__name__)

# Raise your own error
def set_age(age):
    if age < 0:
        raise ValueError("Age cannot be negative")

# Custom exception class
class InsufficientFunds(Exception):
    pass

New in Python 3.14: you can list several exceptions without parentheses when you don’t use as, for example except KeyError, IndexError:. Keep the parentheses if your code must also run on older versions.

Common Python Exceptions

File Handling in Python: open, read, write and with

Always open files with a with block. It closes the file automatically, even if an error occurs.

# Write (creates the file or overwrites it)
with open("notes.txt", "w", encoding="utf-8") as f:
    f.write("Line 1\n")
    f.write("Line 2\n")

# Append to the end
with open("notes.txt", "a", encoding="utf-8") as f:
    f.write("Line 3\n")

# Read the whole file
with open("notes.txt", encoding="utf-8") as f:
    text = f.read()

# Read line by line (memory friendly)
with open("notes.txt", encoding="utf-8") as f:
    for line in f:
        print(line.strip())

File Modes

File Methods

Working with Paths, CSV and JSON

from pathlib import Path
import csv, json

p = Path("data") / "report.txt"
p.parent.mkdir(exist_ok=True)       # create folder if needed
p.write_text("Hello", encoding="utf-8")
print(p.exists(), p.suffix, p.stem) # True .txt report

# CSV
with open("marks.csv", newline="", encoding="utf-8") as f:
    for row in csv.DictReader(f):
        print(row["name"], row["score"])

# JSON
with open("config.json", "w", encoding="utf-8") as f:
    json.dump({"debug": True}, f, indent=2)

with open("config.json", encoding="utf-8") as f:
    config = json.load(f)           # {'debug': True}

Most-Used Python Built-in Functions

Built-in functions work without any import. These 25 cover most day-to-day code.

Python Cheat Sheet FAQs

Is there a free Python cheat sheet PDF?

Yes. Download the free 2-page Python Cheat Sheet PDF. It covers data types, operators, string, list and dictionary methods, loops, functions and file handling, and prints cleanly on A4 or US Letter paper.

What should a beginner learn first in Python?

Start with variables and data types, then strings and lists, then if statements and for loops, then functions. Once those feel easy, learn dictionaries, file handling and exceptions. Classes and modules come last.

What is the difference between a list and a tuple in Python?

A list is mutable, so you can add, remove or change items. A tuple is immutable, so it cannot change after creation. Use a list for collections that grow and a tuple for fixed records like coordinates.

How do I reverse a string in Python?

Use slicing with a step of -1: “Python”[::-1] returns ‘nohtyP’. You can also use “”.join(reversed(“Python”)), but slicing is shorter and faster.

What does strip() do in Python?

strip() returns a copy of a string with leading and trailing whitespace removed. Pass characters to remove those instead: “–hi–“.strip(“-“) returns ‘hi’. It does not remove spaces in the middle of the string.

What is the difference between append() and extend()?

append(x) adds x as a single item, even if x is a list. extend(x) adds each item of x separately. So [1].append([2, 3]) gives [1, [2, 3]], while extend gives [1, 2, 3].

How do I check which Python version I have?

Run python –version (or py –version on Windows, python3 –version on macOS and Linux) in a terminal. Inside Python, run import sys and then print(sys.version).

What’s new in Python 3.14?

Python 3.14 adds template strings (t”…”), lazy evaluation of type annotations, official support for free-threaded Python without the GIL, except clauses without parentheses, and a built-in compression.zstd module.

Is Python hard to learn?

Python is one of the easiest languages for beginners because its syntax reads close to English and needs no semicolons or braces. Most learners can write simple scripts within a few weeks of regular practice.

Can I use this cheat sheet for coding interviews?

Yes. The comparison tables, list and dictionary methods, comprehensions and common mistakes sections cover the Python questions asked most often in technical interviews in the US and India.

Key Takeaways

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