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Asking the user for input until they give a valid response
(22 answers)
Closed 10 months ago.
I'm working on a Python project to get better with passing parameters into functions, so built a small program that takes user input and appends it to a list.
I've got most of that working, but I'm stuck on trying to allow a user to add another input if they want. The program asks if they'd like to add another input, with an if/else to handle a "Y" or "N" answer. That's working for the most part. The problem comes when a user enters an invalid response (anything other than a non-case sensitive 'y' or 'n'). At this point, the program is just displaying the goodbye message and ending. I think it has to do with my while loop, since it's supposed to break out when the new_input() function isn't resolving to true anymore. I want that function to continue to cycle through until the user enters a valid response, which would then cause it to continue and take another input or end appropriately.
Is there a way to get this to work with my combination of an if/else statement or is there another method that would work better? I'll drop the relevant pieces of the program below.
def new_input():
answer = input("Would you like to add more wisdom?(y/n): ")
if answer == "y" or answer == "Y":
return True
elif answer == 'n' or answer == 'N':
return False
else:
print("Invalid input. Please try again!")
def main():
name = input('Please enter your name:')
take_input(name)
while new_input():
take_input(name)
print_lib()
print("Thanks for your brain cells, buddy! Bye bye!")
Thanks for your help!
You can always return True, unless N/n is pressed, this way the program will continue running:
def new_input():
answer = input("Would you like to add more wisdom?(y/n): ")
if answer == "y" or answer == "Y":
return True
elif answer == 'n' or answer == 'N':
return False
else:
print("Invalid input. Please try again!")
return True
I have two files in my text-based game. The variable that is being assigned will be keep_note.
If you enter "Take" the boolean value True is assigned to the have_note-001
but in the next file when if have_note_001 == True I get an error saying
have_note-001 is undefined
If keep_note is == "Take":
have_note_001 = True
Then in the next file I want that True value to travel over to the next file.
If have_note_001 == True: print("This Value Is True")
keep_paper = input("Do you want to Leave the piece of paper or Take it? > ")
if keep_paper == "Take":
have_note_01 = True
if have_note_01 == True:
print("You have chosen to keep the piece of paper")
print("You leave the house with the note(" + note_001 + ")")
This is my next file
from intros.intro_001 import have_note_001
if have_note_01 == True:
print("True")
elif have_note_01 == False:
print("False")
In the file, the import is working.
I am importing the have_note_001. It is just not transferring the value True over. It doesnt seem to remember when you give it that value you in the first file, to the second
How can I have the value assigned to a variable carry over to another file when imported?
I'm not sure what you are asking for is in your best interest. The values stored in variables are already carried over by default when you import the file they are from. However, this type of sporadic architecture is not really considered good practice. Let me give you some feedback on your program. First lets give it some input validation:
# start off setting keep_paper to nothing
keep_paper = ''
# As long as the player does not enter 'take' or 'leave' we are going to
# keep asking them to enter a proper response.
while keep_paper not in ['take', 'leave']:
# here we are going to "try" and ask the player for his choice
try:
# here we are getting input from the user with input(...)
# then converting it into a string with str(...)
# then converting it to lowercase with .lower()
# all together str(input(...)).lower()
keep_paper = str(input("Do you want to Leave the piece of paper or Take it? > ")).lower()
# if the player entered an invalid response such as "53" we will go back
# to the beginning and ask for another response.
except ValueError:
print("Sorry, I didn't understand that.")
# ask the user to provide valid input
continue
if have_note_01 == True:
print("True")
elif have_note_01 == False:
print("False")
Now let's address the main topic of your question. Having the value assigned to a variable carry over on imports. As I've already mentioned, this is generally not something that you want, which is why most Python programs have code including:
if __name__ == "__main__":
# do xyz....
This ensures that xyz is only run if the file is being ran, and will not run if the file is imported.
For good measure, I recommend you checkout: https://github.com/phillipjohnson/text-adventure-tut/tree/master/adventuretutorial, reading over the code in this project will give you a better idea at how you might want to tackle your own project. (The basics of functions, classes and inheritance)
I am learning python and practicing my skills my making a simple text based adventure game.
In the game, I want to ask the player if they are ready to begin. I did this by creating a begin() function:
def begin():
print(raw_input("Are you ready to begin? > "))
while raw_input() != "yes":
if raw_input() == "yes":
break
print(start_adventure())
else:
print("Are you ready to begin? > ")
print(begin())
below this in my code is the function start_adventure()
def start_adventure():
print("Test, Test, Test")
When I run the program it starts up and I get to the point where it asks if I am ready to begin. Then it just loops infinitely and I can only exit the program if I completely close Powershell and restart Powershell. What am I doing wrong? How can I get the loop to stop once the player inputs "yes"?
What do you expect this to do? The solution to your problem is to try to understand what the code does, instead of just throwing stuff together. (Don't worry; at least 80% of us were at that stage at one point!)
As an aside, I strongly recommend using Python 3 instead of Python 2; they made a new version of Python because Python 2 was full of really strange, confusing stuff like input causing security vulnerabilities and 10 / 4 equalling 2.
What do you want this to do?
Repeatedly ask the user whether they are ready to begin until they answer "yes".
Call start_adventure().
Ok. Let's put what we've got so far into a function:
def begin():
while something:
raw_input("Are you ready to begin? > ")
start_adventure()
There are a lot of gaps in here, but it's a start. Currently, we're getting the user's input and throwing it away, because we're not storing it anywhere. Let's fix that.
def begin():
while something:
answer = raw_input("Are you ready to begin? > ")
start_adventure()
This is starting to take shape. We only want to keep looping while answer != "yes"...
def begin():
while answer != "yes":
answer = raw_input("Are you ready to begin? > ")
start_adventure()
Hooray! Let's see if this works!
Traceback (most recent call last):
File "example", line 2, in <module>
while answer != "yes":
NameError: name 'answer' is not defined
Hmm... We haven't set a value for answer yet. In order to make the loop run, it has to be something that isn't equal to "yes". Let's go with "no":
def begin():
answer = "no"
while answer != "yes":
answer = raw_input("Are you ready to begin? > ")
start_adventure()
This will work!
Python 3 Solution
You should not be calling raw_input() multiple times. Simply instantiate x and then wait until the user inputs Y to call your start_adventure function. This should get you started:
def start_adventure():
print('We have started!')
#do something here
def begin():
x = None
while x!='Y':
x = input('Are you ready to begin (Y/N)?')
if x=='Y':
start_adventure()
begin()
Your Raw input function (I'm assuming it works correctly) is never assigned to a variable. Instead you call it in your print statement, print the result of it and then you call it again in your while loop condition.
You never actually satisfy the while loop condition because your input isn't assigned to a variable. Assign Raw_input("Are you ready to begin? >") to a variable to store the input. Then while loop with the variable. Make sure in your while loop when the condition is met you reset the variable to something else.
Your program flow is wrong too, you need to call your raw input function inside the while loop. This will change the while loop condition so that when the condition is met (user types "yes") it won't loop infinitely. Hope this helps!
Example of what you need in code form:
//initialize the condition to no value
condition = None;
#check the condition
while condition != "yes"
#change the condition here based on user input **inside the loop**
condition = raw_input("are you ready to begin? >")
if condition == "yes":
#condition is met do what you need
else:
#condition not met loop again
#nothing needs to go here to print the message again
Ok so in this I have an issue where if the answer is "N" then it will still continue to the else statement. How do I fix this? (this is all in a function, edit: with other if statements that work fine)
if command == "Exit":
exit = 1
while exit == 1:
print("Quit? Y/N:", end="")
ex = input()
if ex == "Y":
quit()
elif ex == "N":
break
else:
print("Err")
The Code Seems To work Fine.
I assumed what you Want to do is : on Entering Exit ask user Y or N if user enters Y you quit the program if user enters N you want to break out of while loop. It works fine for both the cases can you add something else to the question to illustrate the problem.
I would also recommend you to try using return statnment while trying to break from multiple loop or if you are creating function for this purpose.
Make sure You are not entering small alphabets . You can use .upper() function to make sure you always use uppercase.
I am a python newbie and have been asked to carry out some exercises using while and for loops. I have been asked to make a program loop until exit is requested by the user hitting <Return> only. So far I have:
User = raw_input('Enter <Carriage return> only to exit: ')
running = 1
while running == 1:
Run my program
if User == # Not sure what to put here
Break
else
running == 1
I have tried: (as instructed in the exercise)
if User == <Carriage return>
and also
if User == <Return>
but this only results in invalid syntax.
Please could you advise me on how to do this in the simplest way possible.
Thanks
I ran into this page while (no pun) looking for something else. Here is what I use:
while True:
i = input("Enter text (or Enter to quit): ")
if not i:
break
print("Your input:", i)
print("While loop has exited")
The exact thing you want ;)
https://stackoverflow.com/a/22391379/3394391
import sys, select, os
i = 0
while True:
os.system('cls' if os.name == 'nt' else 'clear')
print "I'm doing stuff. Press Enter to stop me!"
print i
if sys.stdin in select.select([sys.stdin], [], [], 0)[0]:
line = raw_input()
break
i += 1
Actually, I suppose you are looking for a code that runs a loop until a key is pressed from the keyboard. Of course, the program shouldn't wait for the user all the time to enter it.
If you use raw_input() in python 2.7 or input() in python 3.0, The program waits for the user to press a key.
If you don't want the program to wait for the user to press a key but still want to run the code, then you got to do a little more complex thing where you need to use kbhit() function in msvcrt module.
Actually, there is a recipe in ActiveState where they addressed this issue. Please follow this link
I think the following links would also help you to understand in much better way.
python cross platform listening for keypresses
How do I get a single keypress at a time
Useful routines from the MS VC++ runtime
I hope this helps you to get your job done.
Use a print statement to see what raw_input returns when you hit enter. Then change your test to compare to that.
This works for python 3.5 using parallel threading. You could easily adapt this to be sensitive to only a specific keystroke.
import time
import threading
# set global variable flag
flag = 1
def normal():
global flag
while flag==1:
print('normal stuff')
time.sleep(2)
if flag==False:
print('The while loop is now closing')
def get_input():
global flag
keystrk=input('Press a key \n')
# thread doesn't continue until key is pressed
print('You pressed: ', keystrk)
flag=False
print('flag is now:', flag)
n=threading.Thread(target=normal)
i=threading.Thread(target=get_input)
n.start()
i.start()
You need to find out what the variable User would look like when you just press Enter. I won't give you the full answer, but a tip: Fire an interpreter and try it out. It's not that hard ;) Notice that print's sep is '\n' by default (was that too much :o)
if repr(User) == repr(''):
break
a very simple solution would be, and I see you have said that you
would like to see the simplest solution possible.
A prompt for the user to continue after halting a loop Etc.
raw_input("Press<enter> to continue")
user_input=input("ENTER SOME POSITIVE INTEGER : ")
if((not user_input) or (int(user_input)<=0)):
print("ENTER SOME POSITIVE INTEGER GREATER THAN ZERO") #print some info
import sys #import
sys.exit(0) #exit program
'''
#(not user_input) checks if user has pressed enter key without entering
# number.
#(int(user_input)<=0) checks if user has entered any number less than or
#equal to zero.
'''
Here is the best and simplest answer. Use try and except calls.
x = randint(1,9)
guess = -1
print "Guess the number below 10:"
while guess != x:
try:
guess = int(raw_input("Guess: "))
if guess < x:
print "Guess higher."
elif guess > x:
print "Guess lower."
else:
print "Correct."
except:
print "You did not put any number."
You are nearly there. the easiest way to get this done would be to search for an empty variable, which is what you get when pressing enter at an input request. My code below is 3.5
running = 1
while running == 1:
user = input(str('Enter <Carriage return> only to exit: '))
if user == '':
running = 0
else:
print('You had one job...')
I recommend to use u\000D. It is the CR in unicode.
Here's a solution (resembling the original) that works:
User = raw_input('Enter <Carriage return> only to exit: ')
while True:
#Run my program
print 'In the loop, User=%r' % (User, )
# Check if the user asked to terminate the loop.
if User == '':
break
# Give the user another chance to exit.
User = raw_input('Enter <Carriage return> only to exit: ')
Note that the code in the original question has several issues:
The if/else is outside the while loop, so the loop will run forever.
The else is missing a colon.
In the else clause, there's a double-equal instead of equal. This doesn't perform an assignment, it is a useless comparison expression.
It doesn't need the running variable, since the if clause performs a break.
If you want your user to press enter, then the raw_input() will return "", so compare the User with "":
User = raw_input('Press enter to exit...')
running = 1
while running == 1:
Run your program
if User == "":
break
else
running == 1
The following works from me:
i = '0'
while len(i) != 0:
i = list(map(int, input(),split()))