My question is about getting a user to pull and item from a list. If the item from the list isn't pulled from the list I want to tell the user that he is incorrect. So my code looks like this:
Body_Type = ['Large', 'Medium', 'Small']
print('Create a Character-')
print('Body Type Choices: ' + str(Body_Type))
bt = input('Enter your Body Type: ')
while bt != Body_Type:
if bt == Body_Type[0:]:
print('Your Body Type is: ' + bt)
else:
print('Invalid Body Type')
What I'm trying to do is make my user create a character. This is just the first part of my first simple project. I want to have him pull from one of the items on the list, being "Large, Medium, Small" respectively. I want it to repeat until the user chooses one of the three. I tried to use or but it seems to feel unorganized and I'd have to break up the list and assign each individual variable.
Thanks in advance!
Several errors here like comparing a string to a list, or random slicing hoping that it would work. And the fact that your input statement is before the loop creates an infinite loop because you're comparing 2 variables of a different type again and again (bt != Body_Type is always True regardless of the content of bt since left hand is a string, right hand is a list).
But it shouldn't be so complex to write some working code.
I would create an infinite loop and break only if choice is in the list:
while True:
bt = input('Enter your Body Type: ')
if bt in Body_Type:
print('Your Body Type is: ' + bt)
break
else:
print('Invalid Body Type')
simpler and clearer (and repeats input if fails). The infinite loop (with an always true condition) allows to avoid double input call & test. Just loop, input the string, and break from the loop if matches.
The key statement you were looking for was bt in Body_Type which tests if the string is within the list.
Related
I'm a little new to Python so I apologise in advance if this is a really simple question but I have been trying to wrap my mind around this problem for a while now.
Simply put, my code is to prompt the user if they have written down a couple of values correctly, If they have I want the loop to continue so the values can be saved to a database. If they have not I would like the code to loop back to the top of the while loop so they can re-enter the values.
For some reason when I enter 'no' It goes through the loop regardless, how may I fix this?
Here's the code below:
while True:
clear()
print("\nPlease input the required data.\n")
in_name = input('Name: ')
in_email = input('Email: ')
in_address = input('Address: ')
clear()
print("\nDoes this look correct?\n")
print("#--START--#\n")
print("Name: " + in_name)
print("Email: " + in_email)
print("Address " + in_address)
print("\n#---END---#\n")
validate == input(">>> ")
if validate == "no":
continue
elif validate == "yes":
print("/nAttempting to copy to the database...")
cursor.execute("""
INSERT INTO contacts(name, email, address)
VALUES (?,?,?)
""", (in_name, in_email, in_address))
conn.commit ()
print ( 'Data entered successfully.\n' )
break
(I should note that this write program is part of a larger program, the loop is nested within another loop that acts as the main menu, perhaps that may help.)
the keyword continue will take you back to the next iteration without finishing the current one, example.
for i in range(5):
if i == 2:
continue
print(i * 5)
This means that when i is 2 it wont print(i=2 * 5), instead it will go up to start the next loop where i=3. The output will be
0
5
15
20
If you use break, it will just completely stop and exit out of the iteration once it reaches this keyword.
I think you're looking for the keyword pass.
'while True:' will always be True, meaning the loop will go on forever. I believe that you'll need to break out of the loop for it to stop. Based on Jorge Alvarez's answer, even changing 'continue' to 'pass' will allow the loop to go forever.
If I understand correctly, you'll need to change the initial 'while True:' statement to test whether validate equals 'no' or 'yes'.
I'm very new at coding, and I'm trying to create a shop list with items and prices on it.
That is, once typed in all the items, the function should calculate the sum and stop the moment you exceed the budget.
So I wrote something like:
def shoplist():
list={"apple":30, "orange":20, "milk":60......}
buy=str(input("What do you want to purchase?")
If buy in list:
While sum<=budget:
sum=sum+??
shoplist ()
I really don't know how to match the input of an item with the price in the list...
My first thought is to use 'if', but it's kinda impractical when you have more than 10 items on the list and random inputs.
I'm in desperate need of help....So any suggestions would be nice!! (or if you have a better solution and think me writing it this way is complete garbage... PLEASE let me know what those better solutions areðŸ˜ðŸ˜ðŸ˜
The code you post will not run in python. list is a builtin and should not be used for a variable name, and is doubly confusing since it refers to a dict object here. input() already returns a str so the cast has no effect. if and while should be lowercase, and there is no indentation, so we have no way of knowing the limits of those statements.
There are so many things wrong, take a look at this:
def shoplist(budget):
prices = {"apple":30, "orange":20, "milk":60}
# Initialise sum
sum = 0
while sum <= budget:
buy = input("What do you want to purchase?")
# Break out of the loop if the user hts <RETURN>
if not buy: break
if buy in prices:
sum += prices[buy] # This gets the price
else:
print("Invalid item", buy)
shoplist(142)
So what have I changed? The budget has to come from somewhere, so I pass it in as a parameter (142, I made that up). I initialise the sum to zero, and I moved the while loop to the outside.
Notice as well lots of whitespace - it makes the code easier to read and has no effect on performance.
Lots of improvements to make. The user should be shown a list of possible items and prices and also how much budget there is left for each purchase. Note as well that it is possible to go over budget since we might only have 30 in the budget but we can still buy milk (which is 60) - we need another check (if statement) in there!
I'll leave the improvements to you. Have fun!
Take a look at this as an example:
# this is a dictionary not a list
# be careful not using python reserved names as variable names
groceries = {
"apple":30,
"orange":20,
"milk":60
}
expenses = 0
budget = 100
cart = []
# while statements, as well as if statements are in lower letter
while expenses < budget:
# input always returns str, no need to cast
user_input = input("What do you want to purchase?")
if user_input not in groceries.keys():
print(f'{user_input} is not available!')
continue
if groceries[user_input] > budget - expenses:
print('You do not have enough budget to buy this')
user_input = input("Are you done shopping?Type 'y' if you are.")
if user_input == 'y':
break
continue
cart.append(user_input)
# this is how you add a number to anotherone
expenses += groceries[user_input]
print("Shopping cart full. You bought {} items and have {} left in your budget.".format(len(cart), budget-expenses))
I've made some changes to your code to make it work, with explanation including using comments indicated by the # symbol.
The two most important things are that all parentheses need to be closed:
fun((x, y) # broken
fun((x, y)) # not broken
and keywords in Python are all lowercase:
if, while, for, not # will work
If, While, For, Not # won't work
You might be confused by True and False, which probably should be lowercase. They've been that way so long that it's too late to change them now.
budget = 100 # You need to initialize variables before using them.
def shoplist():
prices = { # I re-named the price list from list to prices
'apple' : 30, # because list is a reserved keyword. You should only
'orange' : 20, # use the list keyword to initialize list objects.
'milk' : 60, # This type of object is called a dictionary.
} # The dots .... would have caused an error.
# In most programming languages, you need to close all braces ().
# I've renamed buy to item to make it clearer what that variable represents.
item = input('What do you want to purchase? ')
# Also, you don't need to cast the value of input to str;
# it's already a str.
if item in prices:
# If you need an int, you do have to cast from string to int.
count = int(input('How many? '))
cost = count*prices[item] # Access dictionary items using [].
if cost > budget:
print('You can\'t afford that many!')
else:
# You can put data into strings using the % symbol like so:
print('That\'ll be %i.' % cost) # Here %i indicates an int.
else:
print('We don\'t have %s in stock.' % item) # Here %s means str.
shoplist()
A lot of beginners post broken code on StackOverflow without saying that they're getting errors or what those errors are. It's always helpful to post the error messages. Let me know if you have more questions.
I have a while statement which works well and I have a whole section of code that asks the user to input how many names they have which will then ask them for a name that amount of times and then each time a name will be entered.
I need the section of the names entered to be error tapped but I don't know how to do it, as I have a while statement and I may need to put another while statement in, although I have error tapped the section for amount of names in numbers.
Also there is code further on with a dictionary and sorts but I need help with the one section of error tapping started at while currentnum part
print("Please enter each name when asked without any spaces.") #The program will post this
print("Please enter each of your names individually also.") #Program will again post this
names = [] #This is the value of names which will be changed depending on the input
currentnum = 0 #Currentnum value is 0
while True: #While loop as it will revert to the start if question answered incorrectly
try:
numofnames = int(input("How many names do you have? "))
except ValueError: #if the input is not an integer or a whole number it will
print("Sorry that was not a valid input please retry")
continue #it will loop back and ask the question again as it says that the unput was not valid
else:
break #If the input is correct then the loop will break and continue to the next section of the program
while currentnum < numofnames: #This means that while currentnum is smaller than input for numofnames it will continue to ask question. This is another loop
currentnum = currentnum + 1 # every time the question is asked it means that currentnum gets 1 added to it and will continue to ask untill it is the same as the input for numofnames
name = str(input("Enter your name: ")) #Name asked to be entered in string
name = name.upper() #This changes all letters to upper case no matter what so there is no error for upper and lower case or a bigger dictionary showing lower and upper case values.
names.append(name)
Yep. The easiest way to describe what you're doing is to use the .isalpha attribute in an if statement. First you will have to def your while loop
Like the following:
def Loop():
name_input_complete = False
while name_input_complete != True:
string = input("Please input :")
string = str(string)
if string.isalpha():
name_input_complete = True
else:
print("Please do not use numbers and spaces")
Loop()
Loop()
Baisically you have to define the loop and then run it. The if statement(which is the part you should add to your loop) then checks if there is nothing other than letters. If true, your done with error trapping and the loop is exited. The program continues outside the loop. If not then the while is repeated because the Loop() function is called again.
Your code looks very good to me. I dont see what input can the user put that could cause an error, since most data in python can be stringed AND names can be pretty much anything!. If you could comment exactly what error could be caused i might be able to help you
I am trying to create a python array that can hold as many strings as the user enters. I am trying to implement it in a loop, like this :
(Loop:)
Enter the string:
array[1] = (string entered by user)
Enter the next string:
array[2] = (second string entered by user)
....
Enter the nth string:
array[n] = (nth string entered by user)
How can I achieve this? I have heard of dynamic arrays and lists and stuff, but I can't figure them out.
Thank you in advance.
The default lists in Python are dynamic arrays. You can simply initialize it with:
data = []
and use:
data.append(item)
to add an element at the end.
For example:
data = []
while True:
print('Enter the string:')
data.append(input())
This will go on until all the memory of your machine is exhausted.
You can also for instance specify a way to stop asking the user for more data. For instance if the user enters '-1', you can say the loop should stop:
data = []
while True:
print('Enter the string:')
the_input = input()
if the_input == '-1':
break
data.append(the_input)
#do something with the collected data
Now if you for instance run this code: the code will query for input until you enter -1 (I think it is rather obvious how you can change the stopword). Then data contains all data entered before and you can process it somehow.
Try this:
all_the_things = list()
for x in items:
all_the_things.append(x)
For more reading: Python Data Structures
If you want to add to a list, use append
data = []
data.append('whatever')
You haven't asked about how to get the input, so I assume you can do that.
Do bear in mind your computer will not have infinite storage - at some point you will run out of memory if you do this in a loop for ever.
Pretty new to python/programming in general, this is my biggest project yet.
I am writing a program that will do SUVAT equations for you. (SUVAT equations are used to find the displacement, start/end velocity, acceleration and time travelled by an object with constant velocity, you may call them something different.)
I made this list:
variables = ["Displacement", "Start Velocity", "End Velocity", "Acceleration", "Time"]
which is used in the following while/for loop:
a = 0
while a==0:
for variable in variables:
# choice1 is what the user is looking to calculate
choice1 = raw_input("Welcome to Mattin's SVUVAT Simulator! Choose the value you are trying to find. You can pick from " + str(variables))
# will execute the following code when the for loop reaches an item that matches the raw_input
if choice1 == variable:
print "You chave chosen", choice1
variables.remove(variable) #Removes the chosen variable from the list, so the new list can be used later on
a = 1 # Ends the for loop by making the while loop false
# This part is so that the error message will not show when the raw_input does not match with the 4 items in the list the user has not chosen
else:
if choice1 == "Displacement":
pass
elif choice1 == "Start Velocity":
pass
elif choice1 == "End Velocity":
pass
elif choice1 == "Acceleration":
pass
# This error message will show if the input did not match any item in the list
else:
print "Sorry, I didn't understand that, try again. Make sure your spelling is correct (Case Sensitive), and that you did not inlcude the quotation marks."
Hopefully the comments I have written in the code should explain my intentions, if not, feel free to ask anything.
The problem is that when I run the code, and input choice1, the for loop activates the last line of code:
else:
print "Sorry, I didn't understand that, try again. Make sure your spelling is correct (Case Sensitive), and that you did not inlcude the quotation marks."
and then prompts me to enter the input again, and will do this as many times as it needs to get to the item on the list that I am typing.
However, I specifically coded that if what I input does not match the item on the list the for loop is currently checking, but does match one of the other items on the list, then it should pass and loop round to checking the next item.
I am probably doing something stupid, but I don't see it, so please help me figure out what I have to do to get my desired result? I assumed it was the syntax I had wrong so that is why that is the title.
Thanks for any help, I appreciate it.
Besides the problem with the indentation in your pasted code, I would rewrite it as such:
while True:
choice = raw_input('...')
if choice in variables:
print "You chave chosen", choice
# Remove the chosen member from the list
variables = [v for v in variables if v != choice]
# Break out of loop
break
# Print error messages etc.
Also remember that string comparisons are case sensitive. I.e 'Displacement' != 'displacement'.