This is a random code which is similar to my own project code.
When i run it it says UnboundLocalError: local variable 'score' referenced before assignment. Can anyone fix it.
score = 0
def Random_Thing():
Random_Text = input("Random Text")
if Random_Text == "Hello":
score = score + 1
print(score)
def Random_Thing_2():
Random_Text_2 = input("Random Text 2")
if Random_Text_2 == "Hello2":
score = score + 1
print(score)
Random_Thing()
Random_Thing_2()
print(score)
When you define score = 0 at the top, it is in the global scope for the file. By default, functions have only read access to global variables. You cannot change them. Therefore print(score) would work inside a function. But score=score+1 would not.
If you want to change global variable(s) from inside a function, do global var1, var2... at the begining of the function. For your code, you need to do
def Random_Thing():
global score
#your code
def Random_Thing_2():
global score
#your code
Related
def check_answer (q, a, s ):
if q == a :
s += 1
print (f" your score is {s} ")
else :
s -= 1
print (f" your score is {s} ")
i know maybe my english not good but i need help with my problem
i made a quiz project ,
when user enter the right answer I want the program give him more 1 point in his score
but my code does not work good !!
my code
Two options
Use return value to update caller variable
Use global variable so function uses caller's variable s
Note: Option 1 is normally preferred with Option 2 only for simple code.
Issue with Option 2 is global variables enable functions to have hidden (non-obvious, surprising, hard to detect, hard to diagnose) side effects, leading to an increase in complexity--Source
Option 1--use return to update s
def check_answer (q, a, s ):
# a local s is initialized to the passed-in value
if q == a :
s += 1 # update local s in function check_answer
print (f" your score is {s} ")
else :
s -= 1 # update local s in function check_answer
print (f" your score is {s} ")
return s # returns the value of the local s to caller
# Usage (as mentioned by Barmar in comments)
# Initialization (set s to initial value)
s = 0
# ... some code
s = check_answer(q1, a1, s) # s is updated to new value
# ...some more code
s = check_answer(q1, a2, s) # s is udpated to new value
# ...and so on
Option 2: share s as a global variable
def check_answer (q, a):
global s # use s from global scope
if q == a :
s += 1 # updates global variable s
print (f" your score is {s} ")
else :
s -= 1 # updates global variable s
print (f" your score is {s} ")
# Usage
# initialize s (global scope variable i.e. outside function calls)
s = 0
# other code
# ...
check_answer (q1, a1) # global s is updated
# ...
# ...
check_answer(q2, a2) # global s is updated
# ...and so on
# ...
I am attempting to make a simple guessing game for my class with graphics and I'm trying to make an attempt counter. This is the area where my code is going wrong.
def value():
guess = int(input("Enter your guess: "))
if guess > num:
attempts = attempts + 1
turtle.clearscreen()
interface()
tooHigh()
attempt = turtle.Turtle()
attempt.speed(0)
attempt.color("white")
attempt.penup()
attempt.hideturtle()
attempt.goto(-250 , 200)
attempt.write(guess, font=("Courier", 14, "bold"))
value()
elif guess < num:
attempts = attempts + 1
turtle.clearscreen()
interface()
tooLow()
attempt = turtle.Turtle()
attempt.speed(0)
attempt.color("white")
attempt.penup()
attempt.hideturtle()
attempt.goto(-250 , 200)
attempt.write(guess, font=("Courier", 14, "bold"))
value()
elif guess == num:
attempts = attempts + 1
turtle.clearscreen()
interface()
yes()
attempt = turtle.Turtle()
attempt.speed(0)
attempt.color("pink")
attempt.penup()
attempt.hideturtle()
attempt.goto(-250 , 200)
attempt.write(guess, font=("Courier", 14, "bold", "underline"))
print ("Correct!")
else:
print ("ERROR")
def startScreen():
begin = input("Start the game?: ")
if begin == 'yes':
value()
elif begin == 'instructions':
instructions()
startScreen()
elif begin == 'no':
sys.exit()
else:
print ("Unrecognised answer.")
startScreen()
attempts = 0
num = random.randint(1,1000)
interface()
startScreen()
The error I receive is:
Traceback (most recent call last):
File "D:\Desktop\Python Programs\Game.py", line 154, in <module>
`startScreen()`
File "D:\Desktop\Python Programs\Game.py", line 141, in startScreen
`value()`
File "D:\Desktop\Python Programs\Game.py", line 110, in value
`attempts = attempts + 1`
UnboundLocalError: local variable 'attempts' referenced before assignment
It doesn't seem possible to move attempts into the function as it constantly calls itself, resetting attempts each time.
I am unsure why this is occurring so any help would be greatly appreciated. Thanks!
The reason you are getting this error is because of something called variable scope. You have defined the variable attempts outside of the function value, so the function will not recognize any local variable by the name attempts unless you explicitly put the statement global attempts at the beginning of your function. This will tell the function that you want to use the variable attempts that you defined in your main program. That should look like this:
def value():
global attempts
#function code
Alternatively, you can allow your function value to take an argument, and pass the variable attempts into that. That would look something like this:
def value(attempts):
#function code
#you can use the variable attempts as needed, since you're passing it directly into the function
#call the function however you want
attempts = 0
value(attempts)
In the function, when you access a variable for assignment, it by-default is treated as a local variable. So, to make Python know that the variable that you want to modify is a global variable, you do the following:
def value():
global attempts
# rest of your code
The global isn't working properly and it says that
it does not know what text is, even though it is declared global.
def nguess():
answer = random.randint ( 1, 50 )
def check():
global attempts
attempts = 10
global text
attempts -= 1
guess = int(e.get())
if answer == guess:
text.set("yay you gat it right")
btnc.pack_forget()
elif attempts == 0:
text.set("you are out of attempts")
btnc.pack_forget ()
elif guess > answer:
text.set("incorrect! you have "+ str(attempts) + "attempts remaining. Go higher")
elif guess < answer:
text.set("incorrect! you have "+ str(attempts) + "attempts remaining. Go lower")
return
nw = tk.Toplevel(app)
nw.title("guess the number")
nw.geometry("500x150")
lable = Label(nw, text="guess the number between 1 - 50")
lable.pack()
e = Entry(nw, width = 40, borderwidth = 10)
e.pack()
btnc = Button(nw,text = "Check", command = check)
btnc.pack()
btnq = Button ( nw, text="Quit", command=nw.destroy )
btnq.pack()
text = StringVar()
text.set("you have ten attempts remaining ")
guess_attempts = Label (nw,textvariable = text)
guess_attempts.pack()
Well, what's going on is you're trying to get a variable before initialize it i.e. in check function you're calling a global text variable so what it means is you're bringing whatever text variable stores in global namespace, but the problem is text variable isn't exist in global namespace yet because you've created after calling the check function. Below I show an example:
def test():
global variable
print(variable)
test()
variable = 'Hello'
This will raise an error because of what I just explained, so what you have to do is something like this(based on the example):
def test():
global variable
print(variable)
variable = 'Hello'
test()
In short, initialize the text variable before calling the check function which uses global text
how can I make this function working? Is there a good subsitute for global??
position=0
score=0
eggY=300
eggX=0
def egglg():
while True:
global eggX
global eggY
if eggX<330:
eggX+=5
eggY+=0.8
elif eggX>=330:
eggY=eggY+2
if eggY>450:
terminate()
elif eggY<450 and eggY>350 and position ==1:
score+=1
return
#rest of my code, with chaning position to 1 when i press w
egglg()
somehow it returns 0
Since you want to write to the global variables eggX, eggY and score you've to declare all 3 variables global:
position=0
score=0
eggY=300
eggX=0
def egglg():
global eggX, eggY, score
# [...]
Note, the variable position is just read, so there is no necessity to declare it golabal.
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Im new(-ish) to python and I made a game today which after I finished I realised I'd made a big mistake :
inside the functions I had to access and edit variables which where also accessed and changed in other functions and maybe in the future outside the functions. And I don't know how to do that.
I've researched for a long time and found very few things that might solve the problem, I've tried a few, but they haven't worked and I don't understand how to use others.
Could you please try to help me with the problem and if you spot others please tell me, as Im not too good at debugging :(
Here is the code below, its quite big (I've put the variables I need to access and change in bold):
from random import randint
print ("Ghost Game v2.0")
print ("select difficulty")
score = 0
alive = True
difficulty = 0
doors = 0
ghost_door = 0
action = 0
ghost_power = 0
#define the function 'ask_difficulty'
def ask_difficulty() :
difficulty = input ("Hard, Normal, Easy")
set_difficulty()
# define the function 'set_difficulty' which sets the difficulty.
def set_difficulty() :
if difficulty == 'Hard' or 'Normal' or 'Easy' :
if difficulty == 'Hard' :
doors = 2
elif difficulty == 'Normal' :
doors = 3
elif difficulty == 'Easy' :
doors = 5
else:
print ("Invalid input, please type Hard, Normal, or Easy")
ask_difficulty()
# define the function 'ghost_door_choose' which sets the ghost door and the chosen door
def ghost_door_choose(x):
ghost_door = randint (1, x)
print (doors + " doors ahead...")
print ("A ghost behind one.")
print ("Which do you open?")
if doors == 2 :
door = int("Door number 1, or door number 2...")
if 1 or 2 in door :
ghost_or_no()
else :
print ("Invalid input")
ghost_door_choose(difficulty)
elif doors == 3 :
door = int("Door number 1, door number 2, or door number 3")
if 1 or 2 or 3 in door :
ghost_or_no()
else:
print ("Invalid input")
ghost_door_choose(difficulty)
elif doors == 5 :
print("Door number 1, door number 2, door number 3, door number 4, or door number 5.")
if 1 or 2 or 3 or 4 or 5 in door :
ghost_or_no()
else:
print ("Invalid input")
ghost_door_choose(difficulty)
# define the function 'ghost_or_no'
def ghost_or_no() :
if door == ghost_door:
print ("GHOST!!")
print ("Initiating battle...")
battle()
else:
print ("No ghost, you\'ve been lucky, but will luck remain with you...")
score = score + 1
ghost_door_choose(difficulty)
# define the function 'battle' which is the battle program
def battle() :
ghost_power = randint (1, 4) # 1 = Speed, 2 = Strength, 3 = The ghost is not friendly, 4 = The ghost is friendly
print ("You have 3 options")
print ("You can flee, but beware, the ghost may be fast (flee),")
print ("You can battle it, but beware, the ghost might be strong (fight),")
print ("Or you can aproach the ghost and be friendly, but beware, the ghost may not be friendly (aproach)...")
action = input ("What do you choose?")
if flee in action :
action = 1
elif fight in action :
action = 2
elif aproach in action :
action = 3
else :
print ("Invalid input")
battle()
if ghost_power == action :
if action == 1:
print ("Oh no, the ghost\'s power was speed!")
print ("DEFEAT")
print ("You\'r score is " + score)
alive = False
elif action == 2:
print ("Oh no, the ghost\'s power was strength!")
print ("DEFEAT")
print ("You\'r score is " + score)
alive = False
elif action == 3:
print ("Oh no, the ghost wasn\'t friendly ")
alive = False
elif ghost_power == 4 and action == 3 :
print ("Congratulations, The ghost was friendly!")
score = score + 1
ghost_door_choose(difficulty)
elif ghost_power != action and ghost_power != 4 :
if action == 1:
print ("Congratulations, the ghost wasn\'t fast!")
score = score + 1
ghost_door_choose(difficulty)
elif action == 2:
print ("Congratulations, you defeated the ghost!")
score = score +1
ghost_door_choose(difficulty)
elif ghost_power != action and ghost_power == 4 :
if action == 1:
print ("You ran away from a friendly ghost!")
print ("Because you ran away for no reason, your score is now 0")
score = 0
ghost_door_choose(difficulty)
elif action == 1:
print ("You killed a friendly ghost!")
print ("Your score is now 0 because you killed the friendly ghost")
score = 0
ghost_door_choose(difficulty)
#actual game loop
ask_difficulty()
while alive :
ghost_door_choose(doors)
Consider:
x=0
z=22
def func(x,y):
y=22
z+=1
print x,y,z
func('x','y')
When you call func you will get UnboundLocalError: local variable 'z' referenced before assignment
To fix the error in our function, do:
x=0
z=22
def func(x,y):
global z
y=22
z+=1
print x,y,z
The global keyword allows a local reference to a global defined variable to be changed.
Notice too that the local version of x is printed, not the global version. This is what you would expect. The ambiguity is if there is no local version of a value. Python treats globally defined values as read only unless you use the global keyword.
As stated in comments, a class to hold these variables would be better.
Those variables at the top of your script are global and to set them in functions, you have to declare them global in the function. As a smaller example,
score = 0
alive = True
def add_score(value):
"""Add value to score"""
global score
score += value
def kill_kill_kill():
global alive
alive = False
The next step is to create classes, which can get complicated. For instance, if you want to track score by user but a user can have multiple characters which each have their own aliveness, you would start to build classes to represent those things.
The global keyword may be what you are looking for.
For example in the following code.
some_variable = 10
def some_function():
global some_variable
some_variable = 20
This would result in some_variable (in the global scope) referring to the value of 20. Where as it would remain at 10 (in the global scope) without the use of the global keyword.
More on global and local variables here.
A function has its own variable scope - this is true for many languages. This means that once the function finishes executing, the variables cease to exist (and Python's garbage collection will clean them up).
The old-school (and generally frowned upon, not necessarily fairly) way of doing this is to use Global Variables. These are variables you declared outside the scope of the function, usually at the beginning of your source, and can be used throughout your program's various functions and classes.
There are good reasons people don't use global variables much, from performance issues through to getting them confused with locally scoped variables, but they are a quick and easy way to keep information and access it throughout your program.
To use a global, you need to declare within the function that you are using that variable, like this:
MyGlobal="This is a global variable"
def MyFunction():
global MyGlobal
MyGlobal += " and my function has changed it"
if __name__=="__main__":
print MyGlobal
MyFunction()
print MyGlobal
Having said this, the usual way to pass information to and from functions is to use arguments and return values - this is a better design methodology, and the one usually taught. This is more a design method than a change to your code; you write your program with keeping global variables down to an absolute minimum.
To take the above example, this would change our code to the following:
def MyFunction(MyArg):
MyArg+=" and my function has given me a new version of it"
return MyArg
if __name__=="__main__":
MyVariable="This is a variable"
print MyVariable
MyVariable = MyFunction(MyVariable)
print MyVariable
Note that this is much more flexible - I can use it as I have above, to change the value of MyVariable, but I could also use the same function to return the new value to a different variable, keeping the original intact.
I hope this helps, sorry if I was a tad verbose.