conditionals.py

#if statements let you respond to specific scenarios in code
#if statements also need to be followed by a colon

cars = ['audi', 'bmw', 'subaru', 'toyota']

for car in cars:
	if car == 'bmw':
		print(car.upper())
	else:
		print(car.title())

#at the core of every if statement is an expression that can be evualated as either true or false, and it is called a conditional test
#if a conditional test evualates as true, then Python will execute the code following the if statement, and if it is false, then it will ignore the code 
#following the if statement
#capitalization matters. Two values with different capitalization aren't considered equal, even if they are the same word
#however, you can make a something equal to another value, for example, you can use the lower() function 
#one equal sign sets a value to what comes after the equal sign, while two equal signs ask whether or not the two values before/after the equal sign are equal

car = ['Audi', 'bmw']
for car in car: 
	if car.lower() == 'audi':
		print("true")
	else:
		print("false")

#if you want to check whether or not two values are equal, you can use a '!' and a '=' in tandem, like this '!='
#the exclamation point stands for 'not', so '!=' means 'does not equal'

requested_topping = 'mushrooms'

if requested_topping != 'anchovies':
	print("\nHold the anchovies!")

age = 14
if age == '14':
	print("\ntrue")
else:
	print("false")

answer = 17
if answer != 42:
	print("\nThat is not the right answer. Try again!")

age = 19
if age < 21:
	print("\n21 is larger than age.")
if age <= 21:
	print("\n21 is larger than or equal to age.")
if age > 21:
	print("\n21 is smaller than age.")
if age >= 21:
	print("\n21 is smaller than or equal to age.")

#to check if two conditions are true simultaneously, use the 'and' keyword to combine two conditional tests

age_0 = 22
age_1 = 18

if age_0 >= 21 and age_1 >= 21:
	print("\ntrue")
else:
	print("\nfalse")

age_1 = 22

if age_0 >= 21 and age_1 >= 21:
	print("true")
else:
	print("false")

#the keyword 'or' also allows you to check for different conditions, but evualates as true if either conditonal test passes; it doesn't need them both
#an 'or' expression only fails when both tests fail

age_0 = 22
age_1 = 18

if age_0 >= 21 or age_1 >= 21:
	print("\ntrue")
else:
	print("\nfalse")

age_0 = 18

if age_0 >= 21 or age_1 >= 21:
	print("true")
else:
	print("false")

#to see whether or not a specific value is already in a list, you can use the keyword 'in'
#you can use the key word 'not' in conjunction with the keyword 'in' to see if something is not in a list (the keywords are 'not in')

requested_toppings = ['mushrooms', 'onions', 'pineapple']

if 'mushrooms' in requested_toppings:
	print("\ntrue")

if 'pepporoni' not in requested_toppings:
	print("false")

banned_users = ['andrew', 'carolina', 'david']
user = 'marie'

if user not in banned_users:
	print(f"{user.title()}, you can post a response if you wish. Why can you post a response? Simple. Because you're not banned.")

#a boolean expression is another term for a conditional test

#CONDITIONAL TESTS PRACTICE

blessing = "Joni's Blessing"
print("\nIs blessing == Joni's Blessing? I think it is...")
print(blessing == "Joni's Blessing")

print("\nIs blessing == Salubra's Blessing? I think it isn't...")
print(blessing == "Salubra's Blessing")

age = 19
if age >= 18:
	print("\nYou are old enough to vote! (In the US only, that is.... I don't know about anywhere else.)")
	print("Have you registered to vote yet? (I say, knowing full well it's nowhere close to voting time.)")

#there are also if-else statements, which allow you to do an action if a conditional test fails.
#"else" must also be followed by a colon, and if you have another if after the else: statement, you have to indent it, and if you have another else after 
#that, you have to indent that as well.

age = 17
if age >= 18:
	print("\nYou are old enough to vote! (In the US only, that is.... I don't know about anywhere else.)")
	print("Have you registered to vote yet? I say, knowing full well it's nowhere close to voting time.")
else: 
	print("\nSorry, you are too young to vote.")
	print("You can vote when you turn 18 though, and I'm sure it won't be that long!")

#there are also if-elif-else syntaxes, which work by only executing a single action (Python will run each conditional test until one passes, and then it 
#will execute the action for that test and ignore the rest of them.)

age = 12

if age < 4:
	print("Your cost for admission is free.")
elif age < 18:
	print("\nYour admission cost is $25.")
else:
	print("Your admission cost is $40.")

age = 12

if age < 4:
	price = 0
elif age < 18:
	price = 25
else:
	price = 40

print(f"\nYour admission cost is ${price}.")

#you can also add multiple elif blocks.

age = 12

if age < 4:
	price = 0
elif age < 18:
	price = 25
elif age < 65:
	price = 40
else:
	price = 20

print(f"\nYour admission cost is ${price}.")

#you also don't need to finish the if-elif chain with an else block. 

if age < 4:
	price = 0
elif age < 18:
	price = 25
elif age < 65:
	price = 40
elif age >= 65:
	price = 20

print(f"\nYour admission cost is ${price}.")

#while the if-elif-else chain is useful, it is only useful when you only require only one condition to pass.

requested_toppings = ['mushrooms', 'extra cheese']

if 'mushrooms' in requested_toppings:
	print("\nAdding mushrooms.")
if 'pepperoni' in requested_toppings:
	print("Adding pepperoni.")
if 'extra cheese' in requested_toppings:
	print("Adding extra cheese.")

print("\nFinished making your pizza!")

#If you want only one block of code to run, use an if-elif-else syntax; otherwise, use a series of independent if statements.

#ALIEN COLORS #1 PRACTICE

alien_color = 'red'

if alien_color == 'green':
	print("You earned 5 points!")
if alien_color == 'red':
	print("\nYou earned something!")

#ALIEN COLORS #2 PRACTICE

alien_color = 'neon black'

if alien_color == 'green':
	print("You earned 5 points!")
else:
	print("\nYou earned 10 points!")
	print("On a separate note, I'm pretty sure the color 'neon black' doesn't exist.")

#ALIEN COLORS #3 PRACTICE

alien_color = 'red'

if alien_color == 'green':
	score = 5
elif alien_color == 'yellow':
	score = 10
elif alien_color == 'red':
	score = 15

print(f"\nYou earned {score} points!")

age = 14

if age < 2:
	life_stage = 'baby'
elif age >= 2 and age < 4:
	life_stage = 'toddler'
elif age >= 4 and age < 13:
	life_stage = 'kid'
elif age >= 13 and age < 20:
	life_stage = 'teenager'
elif age >= 20 and age < 65:
	life_stage = 'adult'
elif age >= 65:
	life_stage = 'elder'

print(f"\nYou are a {life_stage}.")

favorite_foods = ['steak', 'ribs', 'lamb']

if 'steak' in favorite_foods:
	print("\nYou really like steak!")
if 'ribs' in favorite_foods:
	print("You really like ribs!")
if 'lamb' in favorite_foods:
	print("You really like lamb!\n")
if 'chicken' in favorite_foods:
	print("You really like chicken!")
if 'duck' in favorite_foods:
	print("You really like duck!")

requested_toppings = ['mushrooms', 'green peppers', 'extra cheese']

for requested_topping in requested_toppings:
	if requested_topping == 'green peppers':
		print("Sorry, we're out of green peppers right now.")
	else:
		print(f"Adding {requested_topping}.")

print('\nFinished making your pizza!')

#You can also check if a list is empty

requested_toppings = []

if requested_toppings:
	for requested_topping in requested_toppings:
		print(f"Adding {requested_topping}.")
	print('\nFinished making your pizza!')
else:
	print("\nAre you sure you want a plain pizza?\n")

available_toppings = ['mushrooms', 'olives', 'green peppers', 'pepperoni', 'pineapple', 'extra cheese']

requested_toppings = ['mushrooms', 'french fries', 'extra cheese']

for requested_topping in requested_toppings:
	if requested_topping in available_toppings:
		print(f"Adding {requested_topping}.")
	else:
		print(f"Sorry, we don't have {requested_topping}.")

print("Finished making your pizza!")

#HELLO ADMIN PRACTICE

usernames = ['admin', 'cheesy', 'hollow_geek', 'fireb0rn', 'grog']

for username in usernames:
	if username == 'admin':
		print("\nHello admin. Would you like to see a status report?")
	else:
		print(f"Hello {username}, thank you for logging in again.")

#NO USERS PRACTICE

usernames = []

if usernames:
	for username in usernames:
		if username == 'admin':
			print("\nHello admin. Would you like to see a status report?")
		else:
			print(f"Hello {username}, thank you for logging in again.")
else:
	print("\nWe need to find some users.\n")

#CHECKING USERNAMES PRACTICE

current_users = ['bob', 'joe', 'gary', 'Tike', 'GG']
current_users_decap = [user.lower() for user in current_users]
new_users = ['bob', 'little', 'stuart', 'GG', 'gobble']

for new_user in new_users:
	if new_user.lower() in current_users_decap:
		print("This username has already been chosen.")
	else: 
		print("This username is available.")

#ORDINAL NUMBERS PRACTICE

ordinal_numbers = list(range(1,10))

for ordinal_number in ordinal_numbers:
	if ordinal_number == 1:
		print("\n1st")
	if ordinal_number == 2:
		print("2nd")
	elif ordinal_number == 3:
		print("3rd")
	else:
		print(f"{ordinal_number}th")