问题
http://pastie.org/1966237
I keep getting an unbound local error. I don't understand why it occurs, if the program is running right, it should go straight into the second assignment of the print_et_list function within the main function, looping itself without actually looping. The program only quits using sys.exit() in the hey_user function.
I included the whole program for context, it isn't too long. Let me know if you want to have a look at the text files I use in the program, however I'm sure it's unlikely that it is the source of the problem.
回答1:
UnboundLocalError happens when you read the value of a local variable before you set it. Why is score a local variable rather than a global variable? Because you set it in the function. Consider these two functions:
def foo():
print a
vs
def bar():
a = 1
print a
In foo(), a is global, because it is not set inside the function. In bar(), a is local. Now consider this code:
def baz():
print a
a = 1
Here, a is set within the function, so it's local. But it hasn't been set at the time of the print statement, so you get the UnboundLocalError.
回答2:
You forgot to pass score into hey_user().
回答3:
Looks like it's probably the score variable. It's a local in main(), but you try to reference it in hey_user().
回答4:
If you want to make score a global variable, be sure to declare it with the global statement:
def main (): global score score = 0 question, solution = print_et_list() scoresofar = hey_user (solution) print "\nYour score is now", scoresofar question, solution = print_et_list()
来源：https://stackoverflow.com/questions/6111544/unbound-local-error-in-python-i-cant-shake