import warnings
import numpy as np
np.random.seed(42)
warnings.filterwarnings("ignore")

# Let us start by assigning a value to a variable
x = 5
print(x)

# Variable names can be almost anything: letters, numbers, and underscores.
user_name = "Alex"
favorite_color = "blue"
age = 28
print(user_name, favorite_color, age)

# Case matters! These create two different variables.
height = 180
Height = 175
print(height)
print(Height)

# You cannot use spaces, but underscores are fine.
your_score = 90
# your score = 90  # This will give an error!

# Variable values can be changed any time.
points = 10
print("Points:", points)
points = 15
print("Points updated:", points)

# Store more than one value using multiple variables.
width = 5
height = 7
area = width * height
print("Area:", area)

# Math with variables (addition, subtraction, etc.)
apples = 3
bananas = 4
total_fruit = apples + bananas
print("Total fruit:", total_fruit)

# Combine text using + (called string concatenation)
first_name = "Taylor"
last_name = "Smith"
full_name = first_name + " " + last_name
print("Full Name:", full_name)

# Update a variable based on its own value
counter = 1
counter = counter + 1
print(counter)

# Shorthand: += to add and assign at once.
x = 10
x += 5
print(x)

# Let us look at a few variable types.
score = 95           # integer
pi = 3.1416          # float (decimal number)
name = "Jordan"      # string (text)
is_active = True     # boolean
print(type(score), type(pi), type(name), type(is_active))

# Variables change type as needed.
var = 123
print(type(var))
var = "Now I am a string!"
print(type(var))

# Save user data with input().
user_city = input("What city do you live in? ")
print("Hello to someone from", user_city)

# Use input() for numbers too (string by default)
num_apples = input("How many apples do you want? ")
print("Type of num_apples:", type(num_apples))
num_apples = int(num_apples)
print("Now it is a number:", type(num_apples))

name = input("What is your name? ")
animal = input("Favorite animal? ")
age = input("How old are you? ")
print("Hi", name + ". You love", animal, "and are", age, "years old!")

# Example: swap values between two variables
a = 3
b = 6
a, b = b, a
print("a:", a, "b:", b)

# Delete a variable
x = 22
del x
# print(x)  # This would give an error!

item1 = float(input("Enter price of first item: "))
item2 = float(input("Enter price of second item: "))
item3 = float(input("Enter price of third item: "))
total = item1 + item2 + item3
print("Your total is:", total)

# Challenge: Try changing just one number to see how the total changes!
item1 = float(input("Try a new price for item1: "))
total = item1 + item2 + item3
print("New total:", total)

def show_scope():
    secret = "hidden"
    print("Inside:", secret)

show_scope()
# print(secret)  # This will fail!

# Mistake: Reusing names with different meanings.
score = 50
score = "fifty points"
print(score)

# Mistake: Typos in names silently create new variables.
favorite_color = "blue"
favourite_color = "red"
print(favorite_color, favourite_color)

# Your turn! Follow the instructions above.
pet = input("What is your favorite pet? ")
print("My favorite pet is", pet)

# Try this mini challenge.
guest_name = input("Enter your name: ")
print("Welcome,", guest_name, "!")

# Advanced: Variables in f-strings for formatted output.
city = "Paris"
days = 7
print(f"Trip to {city} for {days} days!")

# Extra: Variables work in calculations and comparisons.
distance = 100
speed = 50
time = distance / speed
print("Travel time (hours):", time)