I am creating a quiz-like program and decided to define the 'while True' loop function (shown below) as a function. To do that, I need the input to change. However, I can't seem to do that no matter how many times I re-format the question. Here is the code:
def whiletrueloop():
while True:
choicenumber=input(choice)
if choicenumber.lower() not in (options):
print(repeatsentence)
else:
break
choice=("What is bigger, an elephant or a mouse?")
choicenumber=("choice1")
options=('elephant','mouse')
repeatsentence=("That isn't an answer!")
whiletrueloop()
if choicenumber=="elephant":
print("Correct!")
elif choicenumber=="mouse":
print("Wrong!")
I think the main problem with the code has to do with the scope of your choicenumber variable. You set it as a global variable with the line
choicenumber = ("choice1")
In the function, it is assigned locally to the input value, but it is the global scope variable that is used in the if-else decision at the end of the code. You can test this by inserting this option at the end of your code:
elif choicenumber == "choice1":
print("Global!")
You'll always get "Global!" displayed, because the local value from the function is ignored in place of the global value.
There are a few ways around this. One is to declare the choicenumber variable as global inside the function:
while True:
global choicenumber
choicenumber=input(choice)
However, using global variables is considered bad practice, for reasons that you can look up.
An alternative is to use the function to return the value of choicenumber in response to the function call:
def whiletrueloop():
while True:
choicenumber=input(choice)
if choicenumber.lower() not in (options):
print(repeatsentence)
else:
return choicenumber
choice=("What is bigger, an elephant or a mouse?")
options=('elephant','mouse')
repeatsentence=("That isn't an answer!")
choicenumber = whiletrueloop()
if choicenumber=="elephant":
print("Correct!")
elif choicenumber=="mouse":
print("Wrong!")
Related
I have a dataset and I want to make a function that does the .get_dummies() so I can use it in a pipeline for specific columns.
When I run dataset = pd.get_dummies(dataset, columns=['Embarked','Sex'], drop_first=True)
alone it works, as in, when I run df.head() I can still see the dummified columns but when I have a function like this,
def dummies(df):
df = pd.get_dummies(df, columns=['Embarked','Sex'], drop_first=True)
return df
Once I run dummies(dataset) it shows me the dummified columsn in that same cell but when I try to dataset.head() it isn't dummified anymore.
What am I doing wrong?
thanks.
You should assign the result of the function to df, call the function like:
dataset=dummies(dataset)
function inside them have their own independent namespace for variable defined there either in the signature or inside
for example
a = 0
def fun(a):
a=23
return a
fun(a)
print("a is",a) #a is 0
here you might think that a will have the value 23 at the end, but that is not the case because the a inside of fun is not the same a outside, when you call fun(a) what happens is that you pass into the function a reference to the real object that is somewhere in memory so the a inside will have the same reference and thus the same value.
With a=23 you're changing what this a points to, which in this example is 23.
And with fun(a) the function itself return a value, but without this being saved somewhere that result get lost.
To update the variable outside you need to reassigned to the result of the function
a = 0
def fun(a):
a=23
return a
a = fun(a)
print("a is",a) #a is 23
which in your case it would be dataset=dummies(dataset)
If you want that your function make changes in-place to the object it receive, you can't use =, you need to use something that the object itself provide to allow modifications in place, for example
this would not work
a = []
def fun2(a):
a=[23]
return a
fun2(a)
print("a is",a) #a is []
but this would
a = []
def fun2(a):
a.append(23)
return a
fun2(a)
print("a is",a) #a is [23]
because we are using a in-place modification method that the object provided, in this example that would be the append method form list
But such modification in place can result in unforeseen result, specially if the object being modify is shared between processes, so I rather recomend the previous approach
I read about "random" and it got me thinking about helping my kid in reading and writing by making a program where a word is shown and she needs to type it. Because it's a small program I could do it quite easliy with procedural programming, but to make it more 'attractive' to her I decided to fool around with tkinter.
Tkinter forces to create functions which can be called through 'command' and now I have a problem.. If I run the check() function, it doesn't get the variables from the dictee() function. I found several answer from nesting a function in a function (undefined variable problems), or passing arguments with return (ended up in recursion), using global (the list of words wouldn't empty) etc etc.. I couldn't get any of them working... I've been looking for answers, but I can't find the correct solution.. Anyone care to shed their light?
Thanks!
"""import nescessary."""
import sys
import random
def main():
"""Setting up the game"""
print("Aliyahs reading game.'\n")
begin = input("do you want to start? yes or no.\n\n")
if begin == "yes":
dictee()
def dictee():
"""Show random words and ask for input."""
words_correct = 0
words_wrong = 0
vocabulary = ['kip', 'hok', 'bal', 'muis', 'gat'
]
words_passed = []
while True:
if vocabulary == []:
print("\n\nThose were all the words.")
print("Words correct: %d" % words_correct)
print("words wrong: %d" % words_wrong)
one_more_time = input("Do you want to go again? yes or no")
if one_more_time == "no":
print("See you next time.")
input("\nPush enter to close.")
sys.exit()
else:
main()
word = random.choice(vocabulary)
print('\x1b[2J')
print("{}".format(word))
print("\n\n")
words_passed.append("{}".format(word))
vocabulary.remove("{}".format(word))
answer = input("Write the word you saw:\n\n")
check()
def check():
'''Cross check word shown with answer given'''
if answer == word:
print("Nice")
words_correct += 1
else:
print("2bad")
words_wrong += 1
try_again = input("\n\nContinue? yes or no\n ")
if try_again.lower() == "no":
exit_game()
else:
dictee()
def exit_game():
'''summarize results and exit after pushing enter'''
print("Words correct: %d" % words_correct)
print("Words wrong: %d" % words_wrong)
input("\nPress Enter to exit.")
sys.exit()
if __name__ == "__main__":
main()
Ive just made few changes here, and run it and got no errors because I dont know what to type in order to get the right results. Anyways all the changes are related to global and redefinition of values.
# say these outside all the functions, in the main block
words_correct = 0
words_wrong = 0
vocabulary = ['kip', 'hok', 'bal', 'muis', 'gat']
words_passed = []
def dictee():
global word, answer
..... #same bunch of codes
def check():
global answer, words_correct, words_wrong
.... #same bunch of codes
Why do we have to say global? Basically because when we define variables they either get defined on local scope or global scope, variables defined on main block(outside of all function) are on global scope, while inside functions are on local scope. Variables defined on global scope can be accessed anywhere and that on local can only be accessed from within where its defined.
Where do we have to use global? We say global where we define the variable or we redefine, or at least this is what I know of. We need to say global where we declare the variable, like, a = 'good', we also need to say global if we are changing it, a = 'bad' or a += 'day' because we are assigning a new value to it. Using global outside of all functions, on the main block, is useless.
Why are we declaring words_correct and words_wrong outside all functions? It is simply because if you declare and set its value to 0 inside dictee(), each time the function is run the value of those variables will change to 0, which means score will always be 0 or 1, so we define it once only, in the main block. Same logic applies to the two lists(vocabulary and words_passed), each time function runs they reset the list to the full list of words, so to get rid of that, just define it once in the main block.
I also think using parameters here might need re-structuring of your code as your calling both function from each other.
Note that we only say global on functions, out side functions all defined variables are open to global scope and can be accessed from anywhere in the code.
PS: This is just my understanding of global over the span of 4 months, do correct me if im wrong anywhere, thanks :D
I am new to programming and one of the problems I have run across is structuring. I am learning Python (3) and am practicing by making a few practical programs. An issue I am running in to is how to get the right flow to the program. I find that as I write a function, I realize that I need it to lead to another function, so I end up calling the next function at the end of the function I'm writing. Then I realize that Python will read the code line-by-line, so I have to have the function I will be calling above the one I am actively writing. The effect is that I end up writing the program in reverse. For example:
#Replaces letters in chosen word with X's
def display_word():
selected_word = list(selected_word)
for x in selected_word:
x = "X"
print (x)
#Function that will display the welcome message when program launches
def start_screen():
user_input = input("Hello and welcome to Hang Man! If you would like to
start a game, please enter 'YES' now!")
user_input = user_input.upper()
if user_input == "YES":
display_word()
else:
print ("You're no fun!")
start_screen()
This is a little tid-bit that I have written in a hang-man program I am practicing with. I started out writing the start_screen function, then realized that I will need to call the display_word function within the start_screen function, but to do that, I will have to define the function before it is called, so I have to write the display_word function above the start_screen function, which effectively has me moving in reverse. My question is whether this is the way things go or if there is a better way to do things. It seems like writing the code in reverse is inefficient, but I am unsure if that is just my inexperience talking.
All functions in Python must be defined before they are used. That does not mean that the function has to be listed above the one it is called from.
The functions can be defined in any order. You just have to make sure the executable portions that start your program, like start_screen(), are called below where the function is defined.
In the case of your hangman program, you are perfectly safe to switch the order of the two functions.
In general, if you have all of your executable code following all of your function definitions, you are good to go to keep them in any order you choose!
Example:
This is perfectly ok. You can even switch them!
def fn1():
print('I am function 1')
fn2()
def fn2():
print ('I am function 2')
fn1()
This is bad!
fn1() #not defined yet!
def fn1():
print('I am function 1')
def fn2():
print ('I am function 2')
This is also bad!
def fn1():
print('I am function 1')
fn2() #not defined yet!
fn1()
def fn2():
print ('I am function 2')
Okay, trying to make a simple game of Guessing Numbers but I can't find the mistake in this code. Still pretty new to python so probably the reason why but I can't figure out what is wrong with it.
import random
from time import sleep
def start():
print("Welcome To The Guessing Game \n Try to guess the number I'm thinking of \n Good luck!")
selectRandomNumber()
guessCheck(number, numberInput=1)
def restart():
print("Creating new number ...")
sleep(1)
print("OK")
selectRandomNumber()
guessCheck(number,numberInput=1)
def selectRandomNumber():
number = random.randint(0,1000)
tries = 0
return
def tryAgain():
while True:
try:
again = int(input("Do you want to play again? y/n:"))
except ValueError:
print("Couldn't understand what you tried to say")
continue
if again == "y" or "yes":
print("Awesome! Lets go")
restart()
elif again == 'n' or "no":
print("Goodbye!")
break
else:
print("Not a valid option")
continue
def guessCheck(number,numberInput=1):
while True:
try:
numberInput = int(input("What number do you think it is?: "))
except ValueError:
print("Couldn't understand that. Try again")
continue
if numberInput > number:
print("Too high")
tries += 1
continue
elif numberInput < number:
print("Too low")
tries += 1
continue
elif numberInput == number:
print("Congrats! You got my number")
tryAgain()
number = selectRandomNumber()
print(number)
start()
Every time I try to run the program I keep getting the same mistake.
It tells me:
Traceback (most recent call last):
File "python", line 60, in <module>
start()
File "python", line 8, in start
guessCheck(number, numberInput)
NameError: name 'number' is not defined
Don't quite understand what that means.
Some help would be appreciated. Thanks!
* UPDATE *
Was able to fix the part about defining the variable but now new problem happened where when I try to run
Same code as before but added
guessCheck(number,numberInput=1)
and also added the variable number at the end
number = selectRandomNumber()
print(number)
start()
when I run it I get this
None # this is from `print(number)` so instead of getting a number here I'm getting `None`
Welcome To The Guessing Game
Try to guess the number I'm thinking of
Good luck!
What number do you think it is?:
The Traceback is telling you this:
We got to start().
start() called guessCheck().
We tried to pass two pieces of information to guessCheck(): the variable names number and numberInput.
We don't have those variables defined yet! numberInput doesn't get defined until once we've already started guessCheck(), and number isn't actually defined anywhere.
As Manoj pointed out in the comments, you probably want number to hold the output of selectRandomNumber(). So, instead of just calling selectRandomNumber() in start(), try number = selectRandomNumber() instead.
You can add a print(number) on the line right after that to make sure number has a value assigned to it.
Now number has a value, going into your call to guessCheck(). That still leaves numberInput undefined though. You can set a default value for function arguments like this:
guessCheck(number, numberInput=1)
That way, when guessCheck is called but numberInput hasn't been defined yet, it will automatically give it the value 1 until you set it explicitly.
You may encounter other issues with your code the way it is. My advice would be to start really simply - build up your game from each individual piece, and only put the pieces together when you're sure you have each one working. That may seem slower, but trying to go too fast will cause misunderstandings like this one.
This question already has answers here:
Variables declared outside function
(3 answers)
Closed 2 years ago.
I have some code and I have assigned a variable as global but when trying to use the variable as validation in a separate function, it throws an exception.
This is the unfinished code (I know it won't work properly at the moment but I want to fix this first) for some school homework, I know there are probably much more efficient was to achieve my purpose but I want to understand why this isn't working.
def mainFunc():
nameList = []
print("1. Add name \n2. Display list \n3. Quit\n")
choice = displayMenu()
if choice == 1:
addName()
elif choice == 2:
displayList()
else:
print("Program Terminating")
def displayMenu():
global answer
answer = int(input("Please enter your choice: "))
answerCheck()
def answerCheck():
if answer == 1 or answer == 2 or answer == 3:
return(answer)
else:
answer = input("Invalid selection, please re-enter: ")
answerCheck()
def addName():
position = int(input("Please enter the position of the name: "))
name = input("Please enter the name you wish to add: ")
remove = nameList[position-1]
nameList.remove(remove)
nameList.add(name,position)
print(nameList)
mainFunc()
Python treats your variable answer as a local variable as in your answerCheck() function, under the else clause, there is an assignment done to the variable answer. Since there is an assignment involved within the local scope, python treats the variable to be in the local scope and this gives your issue. As long as you don't use assignment within your function, the global variable will be read.
You can test this by commenting out the line answer = input("Invalid selection, please re-enter: ") and calling the function. It should work fine.
In order to get your code to work, let python know that you are referencing the global variable using global answer in your answerCheck() function.