🐍 Python For Cybersecurity

age = 20

# Normal if-else (3 lines)
if age >= 18:
    status = "Adult"
else:
    status = "Minor"

# Ternary operator (1 line)
status = "Adult" if age >= 18 else "Minor"

print(status)  # Adult

marks = 85
passing = 40

# Ternary makes it compact
result = "Pass" if marks >= passing else "Fail"
print(result)  # Pass

# Even with multiple conditions
grade = "A" if marks >= 75 else "B" if marks >= 60 else "C"
print(grade)  # A

# Shopping list
shopping_list = ["milk", "bread", "eggs", "rice"]

# Check if milk is in the list
item = "milk"
if item in shopping_list:
    print(f"✅ {item} is already in the list!")
else:
    print(f"❌ {item} not in list, add it!")

# Check if coffee is NOT in the list
if "coffee" not in shopping_list:
    print("☕ Add coffee to the list!")

# Output: ✅ milk is already in the list!
# Output: ☕ Add coffee to the list!

# Check if email has @ symbol
email = "rahul@gmail.com"

if "@" in email and "." in email:
    print("✅ Valid email format")
else:
    print("❌ Invalid email")

# Check for spam keywords
message = "You won a lottery!"
spam_words = ["won", "lottery", "prize", "winner"]

is_spam = any(word in message.lower() for word in spam_words)
if is_spam:
    print("⚠️ This might be spam!")

# Output: ✅ Valid email format
# Output: ⚠️ This might be spam!

# Two variables pointing to SAME object
a = [1, 2, 3]
b = a  # b refers to the SAME list as a

print(a is b)      # True (same object)
print(a == b)      # True (same values too)

# Modify through one variable
b.append(4)
print(a)  # [1, 2, 3, 4] - a changed too!
print(b)  # [1, 2, 3, 4]

# Output: True, True, [1,2,3,4], [1,2,3,4]

# Two variables with SAME values but DIFFERENT objects
x = [1, 2, 3]
y = [1, 2, 3]  # New list with same values

print(x is y)      # False (different objects)
print(x == y)      # True (same values)

# Modify one doesn't affect the other
y.append(4)
print(x)  # [1, 2, 3] - unchanged
print(y)  # [1, 2, 3, 4] - changed

# Output: False, True, [1,2,3], [1,2,3,4]

temperature = 35

# Normal way to think
if temperature > 30:
    print("It's hot outside! 🥵")
    print("Turn on the AC")

print("This runs always")

# Output: It's hot outside! 🥵
# Output: Turn on the AC
# Output: This runs always

battery = 15

if battery < 20:
    print("⚠️ Low battery!")
    print("Please charge your phone")

# When condition is False, nothing prints
battery = 50
if battery < 20:
    print("This won't print")

# Output: ⚠️ Low battery!
# Output: Please charge your phone

age = 16

# Normal if-else
if age >= 18:
    print("You can vote! 🗳️")
    print("You can drive! 🚗")
else:
    print("You're a minor 👶")
    print(f"Wait {18-age} more years")

# Output: You're a minor 👶
# Output: Wait 2 more years

# Try with different age
age = 20
if age >= 18:
    print("You can vote! 🗳️")
else:
    print("You're a minor 👶")

# Output: You can vote! 🗳️

username = "admin"
password = "1234"

# Login check
if username == "admin" and password == "1234":
    print("✅ Login successful!")
    print("Welcome to dashboard")
    print("Redirecting...")
else:
    print("❌ Login failed")
    print("Check username/password")
    print("Try again")

# Output: ✅ Login successful!
# Output: Welcome to dashboard
# Output: Redirecting...

# Wrong credentials
username = "user"
if username == "admin" and password == "1234":
    print("✅ Welcome admin")
else:
    print("❌ Access denied")

marks = 85
income = 300000
sports = True

# Nested conditions - step by step check
if marks >= 80:
    print("✅ Good marks")
    
    # Nested if for income check
    if income < 500000:
        print("✅ Low income")
        
        # Double nested for sports
        if sports:
            print("✅ Sports quota")
            print("🎉 Full scholarship!")
        else:
            print("❌ No sports quota")
            print("📚 Partial scholarship")
    else:
        print("❌ Income too high")
        print("📚 No scholarship")
else:
    print("❌ Marks too low")

# Output: ✅ Good marks
# Output: ✅ Low income
# Output: ✅ Sports quota
# Output: 🎉 Full scholarship!

has_passport = True
age = 25
has_visa = False

# Nested conditions for travel
if has_passport:
    print("✅ Passport OK")
    
    if age >= 18:
        print("✅ Adult")
        
        if has_visa:
            print("✅ Visa OK")
            print("🎫 Ticket confirmed!")
        else:
            print("❌ Need visa")
            print("Apply for visa first")
    else:
        print("❌ Minor needs guardian")
        print("Need parent permission")
else:
    print("❌ Get passport first")
    print("Apply at passport office")

# Output: ✅ Passport OK
# Output: ✅ Adult
# Output: ❌ Need visa
# Output: Apply for visa first

marks = 85

# Elif checks in order
if marks >= 90:
    grade = "A+"
    print("Excellent! 🌟")
elif marks >= 80:
    grade = "A"
    print("Very Good! 👍")
elif marks >= 70:
    grade = "B"
    print("Good! 👌")
elif marks >= 60:
    grade = "C"
    print("Average 📝")
elif marks >= 40:
    grade = "D"
    print("Pass ✅")
else:
    grade = "F"
    print("Fail ❌")

print(f"Grade: {grade}")
# Output: Very Good! 👍
# Output: Grade: A

# Try different marks:
# 95 → Excellent! 🌟, Grade: A+
# 75 → Good! 👌, Grade: B
# 35 → Fail ❌, Grade: F

hour = 14  # 2 PM

# Elif for time greeting
if hour < 12:
    print("Good Morning! ☀️")
    print("Time for breakfast")
elif hour < 17:
    print("Good Afternoon! 🌤️")
    print("Time for lunch")
elif hour < 20:
    print("Good Evening! 🌆")
    print("Time for dinner")
else:
    print("Good Night! 🌙")
    print("Time to sleep")

# Output: Good Afternoon! 🌤️
# Output: Time for lunch

# Different hours:
# 9 AM  → Good Morning! ☀️, breakfast
# 2 PM  → Good Afternoon! 🌤️, lunch
# 6 PM  → Good Evening! 🌆, dinner
# 10 PM → Good Night! 🌙, sleep

temp = 35

# Normal if (2 lines)
if temp > 30:
    print("Hot day!")

# Short-hand if (1 line)
if temp > 30: print("Hot day!")

# Multiple statements? NO!
# ❌ This won't work properly
if temp > 30: print("Hot!"); print("Very hot!")

# Output: Hot day!

battery = 15

# Normal if
if battery < 20:
    print("Low battery!")

# Short-hand if
if battery < 20: print("Low battery!")

# Works with any simple statement
if battery < 20: alert = "Charge now!"

print(alert)  # Charge now!

# Output: Low battery!
# Output: Charge now!

a, b = 10, 20

# Find minimum
minimum = a if a < b else b
print(f"Min: {minimum}")  # Min: 10

# Find maximum
maximum = a if a > b else b
print(f"Max: {maximum}")  # Max: 20

# Absolute value
num = -5
abs_num = num if num >= 0 else -num
print(f"Absolute: {abs_num}")  # Absolute: 5

name = "Rahul"
age = 17

# Status message
status = "Adult" if age >= 18 else "Minor"
print(f"{name} is {status}")

# Plural handling
count = 1
message = f"{count} item" if count == 1 else f"{count} items"
print(message)  # 1 item

count = 5
message = f"{count} item" if count == 1 else f"{count} items"
print(message)  # 5 items

# Initialize counter
i = 1

# Loop while i <= 5
while i <= 5:
    print(f"Count: {i}")
    i += 1  # CRITICAL: update counter!

print("Loop finished!")

# Output:
# Count: 1
# Count: 2
# Count: 3
# Count: 4
# Count: 5
# Loop finished!

✅ i += 1 prevents infinite loop

# Countdown from 5 to 1
countdown = 5

while countdown > 0:
    print(f"{countdown}...")
    countdown -= 1  # Decrease counter

print("🎉 Blast off!")

# Output:
# 5...
# 4...
# 3...
# 2...
# 1...
# 🎉 Blast off!

✅ Decreasing counter works too!

# List of fruits
fruits = ["apple", "banana", "mango", "orange", "grapes"]

for fruit in fruits:
    print(f"I like {fruit}")

print("All fruits printed!")

# Output:
# I like apple
# I like banana
# I like mango
# I like orange
# I like grapes
# All fruits printed!

✅ Loop runs once for each item in the list

# String is a sequence of characters
word = "PYTHON"

for letter in word:
    print(f"Letter: {letter}")

print("Loop finished!")

# Output:
# Letter: P
# Letter: Y
# Letter: T
# Letter: H
# Letter: O
# Letter: N
# Loop finished!

✅ Strings are sequences too - each character becomes an item!

# Calculate average of marks
marks = [85, 90, 78, 92, 88]
total = 0

for mark in marks:
    total += mark

average = total / len(marks)
print(f"Total: {total}")
print(f"Average: {average}")

# Find highest mark
highest = marks[0]
for mark in marks:
    if mark > highest:
        highest = mark
print(f"Highest: {highest}")

cart = [
    {"item": "Shirt", "price": 499},
    {"item": "Jeans", "price": 899},
    {"item": "Shoes", "price": 1299},
    {"item": "Hat", "price": 299}
]

total = 0
print("Your Cart:")
for product in cart:
    print(f"  {product['item']}: ₹{product['price']}")
    total += product['price']

print(f"Total: ₹{total}")

if total > 1000:
    print("You get free shipping!")

# Search for a name in list
students = ["Rahul", "Priya", "Amit", "Neha", "Raj"]
search = "Amit"
found = False

for student in students:
    if student == search:
        found = True
        print(f"✅ Found {search}!")
        break

if not found:
    print(f"❌ {search} not found")

# Count occurrences
numbers = [1, 2, 3, 2, 4, 2, 5]
count = 0
for num in numbers:
    if num == 2:
        count += 1
print(f"Number 2 appears {count} times")

# Filter and transform data
temperatures = [23, 28, 32, 25, 30, 22, 26]
hot_days = 0

for temp in temperatures:
    if temp > 30:
        hot_days += 1
        print(f"🔥 {temp}°C is hot!")
    elif temp > 25:
        print(f"👍 {temp}°C is pleasant")
    else:
        print(f"❄️ {temp}°C is cool")

print(f"Hot days: {hot_days}")

# Search for a number in a list
numbers = [2, 4, 6, 8, 10]
search_for = 5

print(f"Searching for {search_for}...")

for num in numbers:
    print(f"Checking: {num}")
    if num == search_for:
        print(f"✅ Found {search_for}!")
        break
else:
    print(f"❌ {search_for} not found in list")

print("Search complete.")

# Output:
# Searching for 5...
# Checking: 2
# Checking: 4
# Checking: 6
# Checking: 8
# Checking: 10
# ❌ 5 not found in list
# Search complete.

✅ else runs because loop completed all iterations without break

# Search for a number that exists
numbers = [2, 4, 6, 8, 10]
search_for = 6

print(f"Searching for {search_for}...")

for num in numbers:
    print(f"Checking: {num}")
    if num == search_for:
        print(f"✅ Found {search_for}!")
        break
else:
    print(f"❌ {search_for} not found")  # This WON'T run!

print("Search complete.")

# Output:
# Searching for 6...
# Checking: 2
# Checking: 4
# Checking: 6
# ✅ Found 6!
# Search complete.

# Notice: else block did NOT execute!

❌ else skipped because break terminated the loop early

# Process payment attempts
payment_methods = [
    {"type": "credit", "balance": 500},
    {"type": "debit", "balance": 300},
    {"type": "wallet", "balance": 100}
]

amount = 200

for method in payment_methods:
    print(f"Trying {method['type']} card...")
    if method['balance'] >= amount:
        print(f"✅ Payment successful with {method['type']}!")
        break
else:
    print("❌ All payment methods failed!")
    print("Please use another payment method")

# If payment succeeds with credit card:
# else block won't run

# If all cards have insufficient balance:
# else runs with failure message

# Try connecting to servers
servers = ["server1.com", "server2.com", "server3.com"]
connected = False

for server in servers:
    print(f"Attempting to connect to {server}...")
    # Simulate connection attempt
    if server == "server2.com":  # Assume this works
        print(f"✅ Connected to {server}!")
        connected = True
        break
else:
    print("❌ Could not connect to any server")
    print("Check your internet connection")

if connected:
    print("You are now online!")

# This pattern is common in:
# - Load balancers
# - Database connection pools
# - API fallback systems

# Print multiplication table 1-3
print("Multiplication Table (1-3):")
print("-" * 25)

for i in range(1, 4):        # Outer loop - rows
    for j in range(1, 4):    # Inner loop - columns
        # end=" " keeps output on same line
        print(f"{i} x {j} = {i*j:2d}", end="  ")
    print()  # New line after each row
    print()  # Blank line for spacing

# Output:
# Multiplication Table (1-3):
# -------------------------
# 1 x 1 =  1   1 x 2 =  2   1 x 3 =  3  
# 
# 2 x 1 =  2   2 x 2 =  4   2 x 3 =  6  
# 
# 3 x 1 =  3   3 x 2 =  6   3 x 3 =  9

✅ Inner loop runs 3 times for each outer loop iteration (total 9 iterations)

# Print a right-angled triangle
size = 5

print("Triangle Pattern:")
print("-" * 20)

for i in range(1, size + 1):        # Outer: rows
    for j in range(i):               # Inner: columns
        print("*", end=" ")
    print()  # New line after each row

# Output:
# Triangle Pattern:
# --------------------
# * 
# * * 
# * * * 
# * * * * 
# * * * * * 

# The inner loop runs i times - first row 1 star, 
# second row 2 stars, etc.

# Simple month calendar
days_in_month = 31
start_day = 2  # Tuesday (0=Monday, 6=Sunday)

print(" M  T  W  T  F  S  S")
print("-" * 21)

# Print initial spaces
for i in range(start_day):
    print("   ", end="")

# Print days
for day in range(1, days_in_month + 1):
    print(f"{day:3d}", end="")
    if (start_day + day) % 7 == 0:
        print()  # New line after Sunday

# Tic-Tac-Toe board display
board = [
    ['X', 'O', 'X'],
    ['O', 'X', 'O'],
    ['X', 'O', 'X']
]

print("Tic-Tac-Toe Board:")
print("-" * 13)

for i in range(3):
    print("|", end="")
    for j in range(3):
        print(f" {board[i][j]} |", end="")
    print("\n" + "-" * 13)

# Output:
# Tic-Tac-Toe Board:
# -------------
# | X | O | X |
# -------------
# | O | X | O |
# -------------
# | X | O | X |
# -------------

# Temperature readings (3 cities × 4 time slots)
temps = [
    [22, 24, 23, 21],  # City 1
    [18, 20, 19, 17],  # City 2
    [25, 27, 26, 24]   # City 3
]

print("Temperature Readings:")
print("City\t6am\t12pm\t6pm\t12am")

for i, city in enumerate(temps):
    print(f"City {i+1}", end="")
    for temp in city:
        print(f"\t{temp}°C", end="")
    print()

# Calculate average per city
print("\nAverages:")
for i, city in enumerate(temps):
    total = sum(city)
    avg = total / len(city)
    print(f"City {i+1}: {avg:.1f}°C")

# Print chessboard pattern
size = 8

for i in range(size):
    for j in range(size):
        if (i + j) % 2 == 0:
            print("⬜", end="")
        else:
            print("⬛", end="")
    print()

# Output:
# ⬜⬛⬜⬛⬜⬛⬜⬛
# ⬛⬜⬛⬜⬛⬜⬛⬜
# ⬜⬛⬜⬛⬜⬛⬜⬛
# ⬛⬜⬛⬜⬛⬜⬛⬜
# ...

# One argument: range(stop)
print("range(5):", list(range(5)))        # [0, 1, 2, 3, 4]

# Two arguments: range(start, stop)
print("range(2, 7):", list(range(2, 7)))  # [2, 3, 4, 5, 6]

# Three arguments: range(start, stop, step)
print("range(1, 10, 2):", list(range(1, 10, 2)))  # [1, 3, 5, 7, 9]

# Step can be negative
print("range(10, 0, -2):", list(range(10, 0, -2)))  # [10, 8, 6, 4, 2]

# Zero step? ERROR!
# range(1, 10, 0)  # ValueError: step cannot be zero!

# Counting down
print("Countdown from 5:")
for i in range(5, 0, -1):
    print(f"{i}...")

print("Blast off! 🚀")

# Backwards with custom step
print("\nEven numbers backwards:")
print(list(range(20, 0, -2)))  # [20, 18, 16, ..., 2]

# Important: start > stop when step is negative
# This works: range(10, 0, -1)
# This gives empty: range(0, 10, -1) - start < stop with negative step

print("\nEmpty range:")
print(list(range(0, 10, -1)))  # [] - empty!