"""

solutions_basics.py

===================

This script demonstrates all the fundamental Python concepts in one file.

Run it section by section, read the comments, and experiment with the code.

"""

print("\n=== 1. PRINTING & COMMENTS ===")

# Single-line comment

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

print("Hello", "Python") # Multiple arguments

print("Line1\nLine2") # Escape character

print("A", "B", sep="-") # Custom separator

print("End without newline", end=" ")

print(" <- continues on same line")

"""

This is a multi-line comment

(or docstring, if used inside functions/classes).

"""

print("\n=== 2. VARIABLES & DATA TYPES ===")

x = 10 # int

y = 3.14 # float

name = "Khushal" # str

is_learning = True # bool

z = None # NoneType

print(x, type(x))

print(y, type(y))

print(name, type(name))

print(is_learning, type(is_learning))

print(z, type(z))

# Type casting

a = "123"

print(int(a) + 1) # Convert str → int

print("\n=== 3. OPERATORS ===")

a, b = 7, 2

print("Addition:", a + b)

print("Subtraction:", a - b)

print("Multiplication:", a * b)

print("Division:", a / b)

print("Floor Division:", a // b)

print("Modulo:", a % b)

print("Power:", a ** b)

print("Comparison (a > b):", a > b)

print("Equality (a == b):", a == b)

print("Logical AND:", True and False)

print("Logical OR:", True or False)

print("Membership:", "a" in "cat")

print("Identity:", a is b)

print("\n=== 4. INPUT / OUTPUT ===")

# Uncomment to test input

# user_name = input("Enter your name: ")

# print(f"Hello, {user_name}!")

print("\n=== 5. CONDITIONALS ===")

num = 5

if num > 0:

print("Positive number")

elif num == 0:

print("Zero")

else:

print("Negative number")

# Truthy/falsy example

if "":

print("Empty string is truthy")

else:

print("Empty string is falsy")

print("\n=== 6. LOOPS ===")

print("For loop with range:")

for i in range(1, 6):

print(i, end=" ")

print("\nLooping through a list:")

fruits = ["apple", "banana", "cherry"]

for fruit in fruits:

print(fruit)

print("While loop:")

count = 0

while count < 3:

print("Count =", count)

count += 1

print("Using break and continue:")

for i in range(5):

if i == 2:

continue

if i == 4:

break

print(i)

print("\n=== 7. FUNCTIONS ===")

def greet(person):

"""Return a greeting message"""

return f"Hello, {person}!"

print(greet("Khushal"))

# Default argument

def power(base, exp=2):

return base ** exp

print("Square of 3:", power(3))

print("Cube of 3:", power(3, 3))

# Lambda function

double = lambda n: n * 2

print("Double of 5:", double(5))

print("\n=== 8. COLLECTIONS ===")

# List

numbers = [1, 2, 3]

numbers.append(4)

print("List:", numbers)

# Tuple

coordinates = (10, 20)

print("Tuple:", coordinates)

# Set

unique = {1, 2, 2, 3}

print("Set:", unique)

# Dictionary

student = {"name": "Khushal", "age": 25}

print("Dictionary keys:", student.keys())

print("Dictionary values:", student.values())

print("\n=== 9. STRINGS IN DEPTH ===")

text = " Python Basics "

print("Original:", repr(text))

print("Lower:", text.lower())

print("Upper:", text.upper())

print("Strip:", text.strip())

print("Substring [1:6]:", text[1:6])

print("Replace:", text.replace("Python", "Coding"))

print("Split:", text.split())

print("Join:", "-".join(["a", "b", "c"]))

print("\n=== 10. FILE HANDLING ===")

with open("example.txt", "w") as f:

f.write("This is a sample file.\nHello Python!")

with open("example.txt", "r") as f:

print("File contents:\n" + f.read())

print("\n=== 11. EXCEPTIONS ===")

try:

result = 10 / 0

except ZeroDivisionError:

print("Error: Division by zero not allowed.")

finally:

print("This block always runs.")

print("\n=== 12. CLASSES & OBJECTS ===")

class Person:

def __init__(self, name, age):

self.name = name

self.age = age

def introduce(self):

return f"My name is {self.name}, I am {self.age} years old."

p1 = Person("Khushal", 25)

print(p1.introduce())

# Inheritance

class Student(Person):

def __init__(self, name, age, course):

super().__init__(name, age)

self.course = course

def introduce(self):

return super().introduce() + f" I study {self.course}."

s1 = Student("Amit", 20, "Python")

print(s1.introduce())

print("\n=== END OF BASICS ===")

print("You have completed the Python basics tour!")