In the ever-evolving world of programming, having a comprehensive cheat sheet can significantly enhance your coding efficiency and effectiveness. This article provides an extensive Python 3 cheat sheet in PDF format, designed to be a go-to resource for both beginners and experienced developers. Whether you’re brushing up on your skills or diving into Python 3 for the first time, this guide covers all the essential aspects of the language.

Table of Contents

  1. Introduction to Python 3
  2. Basic Syntax and Structure
  3. Data Types and Variables
  4. Operators and Expressions
  5. Control Flow Statements
  6. Functions and Modules
  7. File Handling
  8. Exception Handling
  9. Object-Oriented Programming
  10. Libraries and Frameworks
  11. Common Built-in Functions
  12. Conclusion

Introduction to Python 3

Python 3 is a powerful, versatile, and easy-to-learn programming language that is widely used for web development, data analysis, artificial intelligence, scientific computing, and more. Its simplicity and readability make it an ideal choice for both beginners and seasoned programmers. With a vast standard library and a supportive community, Python 3 continues to grow in popularity.

Basic Syntax and Structure

Comments

Comments in Python are indicated by the # symbol. Multi-line comments can be achieved using triple quotes (''' or """).

# This is a single-line comment
"""
This is a
multi-line comment
"""

Indentation

Python uses indentation to define blocks of code. Proper indentation is crucial as it affects the code’s execution.

if True:
    print("Hello, World!")

Variables and Assignments

Variables in Python do not require explicit declaration to reserve memory space. The assignment is done using the = operator.

x = 5
y = "Hello"

Data Types and Variables

Numeric Types

  • int: Integer values
  • float: Floating-point values
  • complex: Complex numbers
num1 = 10       # int
num2 = 10.5     # float
num3 = 1 + 2j   # complex

Strings

Strings are arrays of bytes representing Unicode characters. They can be enclosed in single, double, or triple quotes.

str1 = 'Hello'
str2 = "World"
str3 = '''Python 3'''

Lists

Lists are ordered, mutable collections of items.

my_list = [1, 2, 3, 4, 5]

Tuples

Tuples are ordered, immutable collections of items.

my_tuple = (1, 2, 3, 4, 5)

Dictionaries

Dictionaries are unordered collections of key-value pairs.

my_dict = {'name': 'John', 'age': 25}

Sets

Sets are unordered collections of unique items.

my_set = {1, 2, 3, 4, 5}

Operators and Expressions

Arithmetic Operators

  • + : Addition
  • - : Subtraction
  • * : Multiplication
  • / : Division
  • % : Modulus
  • ** : Exponentiation
  • // : Floor division
a = 10
b = 3
print(a + b)  # 13
print(a - b)  # 7
print(a * b)  # 30
print(a / b)  # 3.3333333333333335
print(a % b)  # 1
print(a ** b) # 1000
print(a // b) # 3

Comparison Operators

  • == : Equal
  • != : Not equal
  • > : Greater than
  • < : Less than
  • >= : Greater than or equal to
  • <= : Less than or equal to
x = 5
y = 3
print(x == y)  # False
print(x != y)  # True
print(x > y)   # True
print(x < y)   # False
print(x >= y)  # True
print(x <= y)  # False

Logical Operators

  • and : Logical AND
  • or : Logical OR
  • not : Logical NOT
a = True
b = False
print(a and b) # False
print(a or b)  # True
print(not a)   # False

Control Flow Statements

If Statements

x = 10
if x > 5:
    print("x is greater than 5")
elif x == 5:
    print("x is equal to 5")
else:
    print("x is less than 5")

For Loops

for i in range(5):
    print(i)

While Loops

count = 0
while count < 5:
    print(count)
    count += 1

Functions and Modules

Defining Functions

Functions are defined using the def keyword.

def greet(name):
    return f"Hello, {name}!"

Importing Modules

Modules can be imported using the import keyword.

import math
print(math.sqrt(16))

Lambda Functions

Lambda functions are small anonymous functions defined using the lambda keyword.

square = lambda x: x * x
print(square(5))  # 25

File Handling

Python provides various functions for file operations.

Opening a File

file = open("example.txt", "r")

Reading a File

content = file.read()
print(content)
file.close()

Writing to a File

file = open("example.txt", "w")
file.write("Hello, World!")
file.close()

Exception Handling

Exception handling in Python is done using the try, except, else, and finally blocks.

try:
    x = 1 / 0
except ZeroDivisionError:
    print("Cannot divide by zero")
else:
    print("No exceptions occurred")
finally:
    print("This will execute no matter what")

Object-Oriented Programming

Python supports OOP, which includes the use of classes and objects.

Creating a Class

class Dog:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def bark(self):
        return "Woof!"

my_dog = Dog("Buddy", 3)
print(my_dog.bark())  # Woof!

Inheritance

class Animal:
    def __init__(self, name):
        self.name = name

    def speak(self):
        raise NotImplementedError

class Dog(Animal):
    def speak(self):
        return "Woof!"

my_dog = Dog("Buddy")
print(my_dog.speak())  # Woof!

Libraries and Frameworks

Python’s extensive libraries and frameworks facilitate various functionalities.

NumPy

NumPy is a library for numerical computations.

import numpy as np
arr = np.array([1, 2, 3, 4, 5])
print(arr)

Pandas

Pandas is used for data manipulation and analysis.

import pandas as pd
data = {'Name': ['John', 'Anna', 'Peter', 'Linda'],
        'Age': [28, 24, 35, 32]}
df = pd.DataFrame(data)
print(df)

Django

Django is a high-level web framework.

# Sample view in Django
from django.http import HttpResponse

def hello(request):
    return HttpResponse("Hello, World!")

Common Built-in Functions

print()

Prints to the console.

print("Hello, World!")

len()

Returns the length of an object.

print(len("Hello"))  # 5

type()

Returns the type of an object.

print(type(5))  # <class 'int'>

range()

Generates a sequence of numbers.

for i in range(5):
    print(i)

This comprehensive Python 3 cheat sheet is designed to be an essential resource for anyone working with Python. From basic syntax and data types to advanced topics like object-oriented programming and popular libraries, this guide covers it all. We hope this cheat sheet will help you enhance your Python programming skills and become more efficient in your coding endeavors.

If you want to read more information about how to boost traffic on your Website just visit –> The Insider’s Views “https://www.theinsidersviews.com/search/label/SEO”.

Download Link 👇

Telegram Group Join Now
WhatsApp Group Join Now
Instagram Group Join Now

By aczone

Leave a Reply

Your email address will not be published. Required fields are marked *