Python 0 to Hero

# Your first Python program!
print("Hello, World!")

# Print multiple lines
print("Welcome to Python!")
print("Let's start coding! 🚀")

# String - text data
name = "Om Pandey"

# Integer - whole numbers
age = 21

# Float - decimal numbers
height = 5.9

# Boolean - True or False
is_developer = True

# Check types
print(type(name))      # <class 'str'>
print(type(age))       # <class 'int'>
print(type(height))    # <class 'float'>
print(type(is_developer)) # <class 'bool'>

# Print variables
print(f"Hi, I'm {name} and I'm {age} years old!")

# Creating a list
fruits = ["apple", "banana", "cherry"]
numbers = [1, 2, 3, 4, 5]

# Access items (index starts at 0)
print(fruits[0])      # apple
print(fruits[-1])     # cherry (last item)

# Add items
fruits.append("orange")
print(fruits)         # ['apple', 'banana', 'cherry', 'orange']

# Remove items
fruits.remove("banana")
print(fruits)         # ['apple', 'cherry', 'orange']

# List length
print(len(fruits))    # 3

# List slicing
print(numbers[1:4])   # [2, 3, 4]

# Arithmetic Operators
a = 10
b = 3

print(a + b)   # Addition: 13
print(a - b)   # Subtraction: 7
print(a * b)   # Multiplication: 30
print(a / b)   # Division: 3.333...
print(a // b)  # Floor Division: 3
print(a % b)   # Modulus: 1
print(a ** b)  # Exponent: 1000

# Comparison Operators
print(a > b)   # True
print(a == b)  # False
print(a != b)  # True

# Logical Operators
print(True and False)  # False
print(True or False)   # True
print(not True)        # False

name = "Om"
age = 21

# f-strings (Recommended - Python 3.6+)
print(f"Hello, my name is {name} and I'm {age}")

# .format() method
print("Hello, my name is {} and I'm {}".format(name, age))

# % operator (old style)
print("Hello, my name is %s and I'm %d" % (name, age))

# Format numbers
price = 49.99
print(f"Price: ${price:.2f}")  # Price: $49.99

# Padding
print(f"{name:>10}")  # Right align, pad to 10
print(f"{name:<10}")  # Left align, pad to 10

text = "Hello, Python World!"

# Length
print(len(text))         # 20

# Case conversion
print(text.upper())       # HELLO, PYTHON WORLD!
print(text.lower())       # hello, python world!
print(text.title())       # Hello, Python World!

# Find and replace
print(text.find("Python"))     # 7 (index)
print(text.replace("World", "Universe"))

# Split and join
words = text.split(" ")
print(words)              # ['Hello,', 'Python', 'World!']
print("-".join(words))    # Hello,-Python-World!

# Strip whitespace
messy = "  hello  "
print(messy.strip())      # "hello"

# Check content
print(text.startswith("Hello"))  # True
print("Python" in text)         # True

age = 18

# Simple if-else
if age >= 18:
    print("You are an adult!")
else:
    print("You are a minor!")

# Multiple conditions with elif
score = 85

if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
elif score >= 70:
    grade = "C"
else:
    grade = "F"

print(f"Your grade: {grade}")

# Ternary operator (one-liner)
status = "adult" if age >= 18 else "minor"
print(status)

# For loop with range
for i in range(5):
    print(f"Count: {i}")

# For loop with list
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(f"I love {fruit}!")

# While loop
count = 0
while count < 3:
    print(f"Count is {count}")
    count += 1

# Break and Continue
for i in range(10):
    if i == 3:
        continue  # Skip 3
    if i == 7:
        break     # Stop at 7
    print(i)

# List comprehension
squares = [x**2 for x in range(5)]
print(squares)  # [0, 1, 4, 9, 16]

# Basic function
def greet():
    print("Hello, World!")

greet()  # Call the function

# Function with parameters
def greet_person(name):
    print(f"Hello, {name}!")

greet_person("Om")

# Function with return value
def add(a, b):
    return a + b

result = add(5, 3)
print(f"Sum: {result}")  # Sum: 8

# Default parameters
def power(base, exp=2):
    return base ** exp

print(power(3))      # 9 (3^2)
print(power(3, 3))   # 27 (3^3)

# Lambda functions (one-liners)
square = lambda x: x ** 2
print(square(5))  # 25

# Creating a dictionary
person = {
    "name": "Om Pandey",
    "age": 21,
    "city": "Kathmandu",
    "is_developer": True
}

# Access values
print(person["name"])      # Om Pandey
print(person.get("age"))   # 21

# Add or update
person["email"] = "[email protected]"
person["age"] = 22

# Remove items
del person["city"]

# Loop through dictionary
for key, value in person.items():
    print(f"{key}: {value}")

# Dictionary methods
print(person.keys())    # All keys
print(person.values())  # All values
print(len(person))       # Number of items

# Getting user input
name = input("Enter your name: ")
print(f"Hello, {name}!")

# Input is always a string - convert for numbers
age = int(input("Enter your age: "))
print(f"Next year you'll be {age + 1}")

# Multiple outputs
print("Hello", "World", sep="-")  # Hello-World
print("Line 1", end=" | ")
print("Line 2")  # Line 1 | Line 2

# File I/O
# Writing to file
with open("test.txt", "w") as file:
    file.write("Hello, File!")

# Reading from file
with open("test.txt", "r") as file:
    content = file.read()
    print(content)

# Basic print
print("Hello, World!")

# Print with variables
name = "Om"
print("Name:", name)

# Formatted output
score = 95.5678
print(f"Score: {score:.2f}")  # Score: 95.57

# Table-like output
print(f"{'Name':<15}{'Age':>5}")
print(f"{'Om Pandey':<15}{21:>5}")
print(f"{'John Doe':<15}{25:>5}")

# Special characters
print("Line 1\nLine 2")       # New line
print("Col1\tCol2\tCol3")     # Tab
print("He said \"Hello!\"")   # Escape quotes

# Colorful output (using ANSI codes)
print("\033[92m✓ Success!\033[0m")   # Green
print("\033[91m✗ Error!\033[0m")     # Red
print("\033[93m⚠ Warning!\033[0m")   # Yellow

# ASCII Art Fun!
print("""
   🐍 PYTHON 🐍
 ╔═══════════╗
 ║  Hello!   ║
 ╚═══════════╝
""")