user_input_while_loops.py

"""This is where I'm going to be working on the user input and while loops
section of the Python book."""

import os
def clear():
    """Clear terminal text."""
    os.system('clear')

clear()

# The input() function pauses your program and waits for the user to enter some text.
# Once python receives the user's input, it assigns it to a variable to make it easier to work with.

#!!NOTE: SUBLIME TEXT AND MANY OTHER TEXT EDITORS DON'T RUN PROGRAMS THAT ASK THE USER FOR INPUT!!
#I'm going to use GitHub for this, most likely, and just paste the code here when it's done.

message = input("tell me something, and I'll repeat it back to you: ")
print(message)

# Each time you use the input function you should include a clear, easy to
# follow prompt that tells the user exaxctly what kind of info you're looking for.

# It's also good practice to have a colon and/or a space so that it's clear to the
# user where to type.

name = input("Please enter your name: ")
print(f"Hello {name}!")

# Sometimes you'll want to write a prompt that's longer than one line. You can assign your
# prompt to a variable and pass that variable to the input function. This allows you to build your
# prompt over several lines, then include a clean input() statement.

prompt = "If you tell us who you are, we can personalize the messages you see."
prompt += "\nWhat is your first name? "

name = input(prompt)
print(f"Hello {name}!")

# In the example above, the operator += takes the string that was assigned to prompt and
# adds the new string onto the end.

# When you use the input function, Python interprets everthing the user enters as a string.

age = input("How old are you? ")
print(f"You are {age} years old.")

# The user enters their age (a number), but when we ask Python for the value of age,
# it returns the age in quotes (or it would if it wasn't GitHub, I think)
# If all we wanted was to print the input, this is fine, but if we try to use the input
# as a number, we would get an error (again, if it wasn't GitHub, then yeah, I think so)

# When you try to use an input to do a numerical expression, Python produces an
# error because it can't compare a string to an integer. We can fix
# this by using the int() function.

age = input("How old are you? ")
age = int(age)
if age > 10:
    print("True")

height = input("How tall are you, in inches? ")
height = int(height)

if height >= 48:
    print("\nYou're tall enough to ride!")
else:
    print("\nSorry, but you're not tall enough to ride yet.")

# A useful tool for working with numerical info is the modulo operator (%),
# which divides one number by another and returns the remainder.

randoNumber = 4 % 3
print(randoNumber)

randoNumber = 5 % 3
print(randoNumber)

randoNumber = 6 % 3
print(randoNumber)

randoNumber = 7 % 3
print(randoNumber)

# The modulo operator doesn't tell you how many times one number fits into another,
# just what the remainder is.

# When one number is divisible by another number, the remainder is 0, so the modulo operator will
# always return 0. We can use this to determine if a number is even or odd.

number = input("Tell me a number, and I'll tell you if it's even or odd. ")
number = int(number)

if number % 2 == 0:
    print(f"The number {number} is even.")
else:
    print(f"The number {number} is odd.")

# RENTAL CAR PRACTICE:

rentalCar = input("What kind of car would you like? ")
print(f"Let's see if I can get you a {rentalCar}.")

# RESTAURANT SEATING PRACTICE:

seating = input("How many people are in your dinner group? ")
seating = int(seating)

if seating > 8:
    print("I'm sorry, but you have to wait for a table.")
else:
    print("Your table is ready!")

# MULTIPLES OF 10 PRACTICE

tenMultiples = input("Give me a number, and I'll tell you if it's a multiple of 10. ")
tenMultiples = int(tenMultiples)

if tenMultiples % 10 == 0:
    print("Your number is a multiple of 10.")
else:
    print("Your number is not a multiple of 10.")

# While loops run as long as, or while, a certain condition is true.

current_number = 1
while current_number <= 5:
    print(current_number)
    current_number += 1

prompt = "\nTell me something and I'll repeat it back to you."
prompt += "\nEnter 'quit' to end the program. "

message = ""
while message != 'quit':
    message = input(prompt)

    if message != 'quit':
        print(message)

# For a program that should run only as long as many conditions are true, we can define
# one variable that determines whether or not the entire program is active. This variable,
# called a flag, acts as a signal to the program. We can run our programs so that they run only
# while the value of the flag is set to True.

prompt = "\nTell me something and I'll repeat it back to you. (2nd)"
prompt += "\nEnter 'quit' to end the program. "

active = True
while active:
    message = input(prompt)

    if message == 'quit':
        active  = False
    else:
        print(message)

prompt = "\nPlease enter the name of every city you have visited "
prompt += "\n(Enter quit when you are done.): "

while True:
    city = input(prompt)

    if city == 'quit':
        break
    else:
        print(f"I would love to go to {city.title()}")

# You can use break to quit a for loop that's working through a list or dictionary as well.

# We can also use the continue statement to return to the beginning of a loop based on the result of
# a conditional test

current_number = 0
while current_number < 10:
    current_number += 1
    if current_number % 2 == 0:
        continue # Returns to start, does not execute ln 172

    print (current_number)

# Every while loop needs some way to stop so it doesn't run forever.
x = 1
while x < 5: # This loop will stop after x is 5
    print(x)
    x += 1

# x = 1
# while x <= 5: # This loop will never end
#     print (x)

# Test every while loop to make sure the program stops when it's meant to.
# A least one part of the program can break the loop or make it reach a
# false condition. If a program ever gets stuck in an infinite while loop,
# press ctr-c or close the terminal window.

# Some editors (Sublime Text, etc.) have an embedded output window. In this case,
# the editor might have to be closed to end the loop. Try clicking in the output
# window of the editor before pressing ctr-c, and the loop should cancel.

# PIZZA TOPPINGS PRACTICE

while True:
    toppings = input("What topping do you want to add to your pizza? To stop, type in 'quit'. ")
    if toppings != 'quit':
        print(f"I'll add {toppings} to your pizza.")
    else:
        break


# MOVIE TICKETS PRACTICE

while True:
    ticket_price = input("How old are you (Enter 'quit' when done)? ")

    if ticket_price == 'quit':
        break
    elif int(ticket_price) < 3:
        print("Your ticket is free.")
    elif int(ticket_price) >= 3 and int(ticket_price) < 12:
        print("Your ticket will cost $10.")
    elif int(ticket_price) > 12:
        print("Your ticket will cost $15.")

# To keep track of users and info, we need to use lists / dictionaries with our while loops.
# A for loop is effective for looping through a list, but you shouldn't modify a list inside
# a for loop because Python will have trouble keeping track of the items in the list.
# To modify a list as you work through it, use a while loop, which will allow you to collect,
# store, and organize lots of input to examine and report on later.

# You can also use remove() in a while loop.

pets = ['dog', 'cat', 'dog', 'goldfish', 'cat', 'rabbit', 'cat']
print(pets)

while 'cat' in pets:
    pets.remove('cat')

print(pets)

# You can prompt for as much input as you need in each pass through a while loop.

responses = {}

# Set a flag to indicate that polling is active.
polling_active = True

while polling_active:
    # Prompt for the person's name and response.
    name = input("What is your name? ")
    response = input("What mountain would you like to climb? ")

    # Store the response in the dictionary.
    responses[name] = response

    # Find out if anyone else is going to take the poll.
    repeat = input("Would you like to let another person respond (yes / no)? ")
    if repeat == 'no':
        polling_active = False

    # Polling is complete, show the results.

print("\n--Poll Results--")
for name, response in responses.items():
    print(f"{name} would like to climb {response}.")

# DELI PRACTICE

sandwich_orders = ['veggie', 'grilled cheese', 'turkey', 'roast beef']
finished_sandwiches = []

while sandwich_orders:
    current_sandwich = sandwich_orders.pop()
    print(f"I'm working on your {current_sandwich} sandwich.")
    finished_sandwiches.append(current_sandwich)

print("\n")
for sandwich in finished_sandwiches:
    print(f"I made a {sandwich} sandwich.")

# NO PASTRAMI PRACTICE

sandwich_orders = [
    'pastrami', 'veggie', 'grilled cheese', 'pastrami',
    'turkey', 'roast beef', 'pastrami']
finished_sandwiches = []

print("I'm sorry, we're all out of pastrami today.")
while 'pastrami' in sandwich_orders:
    sandwich_orders.remove('pastrami')

print("\n")
while sandwich_orders:
    current_sandwich = sandwich_orders.pop()
    print(f"I'm working on your {current_sandwich} sandwich.")
    finished_sandwiches.append(current_sandwich)

print("\n")
for sandwich in finished_sandwiches:
    print(f"I made a {sandwich} sandwich.")

# DREAM VACATION PRACTICE

polling = True
responses = {}

while polling:
    name = input("What's your name? ")
    response = input("If you could go to any place right now, where would it be? ")

    # Add name and response to the dictionary
    responses[name] = response

    poll_again = input("Will anyone else be taking this poll (yes / no)? ")
    if poll_again == 'no':
        polling = False

print("\n---Poll Results---")
for name, response in responses.items():
    print(f"\n{name} would like to go to {response}")