变量未定义，即使它存在

Question

这是我为侧卫任务编写的简单代码：

import random

congruent = open('congruent.txt', 'r')
incongruent = open('incongruent.txt', 'r')

def createList(file):
    lst = []
    for row in file:
        lst.append(row.strip('\n'))
    return lst
    file.close()

lstCongruent = createList(congruent)
lstIncongruent = createList(incongruent)

nr_trials = 20

def middleString(txt):
    middle = txt[(len(txt)-1)//2]
    return middle
    
def checkCongruency(item):
    if item in lstCongruent:
        correctCongruentAnswers = 0
        correctCongruentAnswers += 1
        return correctCongruentAnswers
    elif item in lstIncongruent:
        correctIncongruentAnswers = 0
        correctIncongruentAnswers += 1
        return correctIncongruentAnswers
            

for i in range(nr_trials):
    rndItem = random.choice(lstCongruent + lstIncongruent)
    print(rndItem)
    answer = input('Please write your answer: ')
    if answer == 'STOP':
        exit()
    while answer != 'F' and answer != 'J':
        print('\33[91m Please type only F or J \33[0m')
        break
        
    if middleString(rndItem) == '<' and answer == 'F':
        print('Correct answer!')
        checkCongruency(rndItem)
    elif middleString(rndItem) == '>' and answer == 'J':
        print('Correct answer!')
        checkCongruency(rndItem)
    else:
        print('Incorrect answer')
 
       
print('Correct congruent answers: ', correctCongruentAnswers)
print('Correct incongruent answers: ', correctIncongruentAnswers)

但是当我运行它时，我得到：

File "main.py", line 68, in <module>
    print('Correct congruent answers: ', correctCongruentAnswers)
NameError: name 'correctCongruentAnswers' is not defined

有没有办法在不完全更改代码的情况下解决这个问题？ 我尝试了不同的东西，比如在 for 循环中定义函数或其他一些东西，但它不起作用。

Answer 1

方法中的变量不会存在于主脚本中。 如果您希望使用checkCongruency correctCongruantAnswers中的正确CongruantAnswers，则必须在运行checkCongruency()时创建一个新变量来接收此值。

if middleString(rndItem) == '<' and answer == 'F':
    print('Correct answer!')
    congruency_result = checkCongruency(rndItem)
elif middleString(rndItem) == '>' and answer == 'J':
    print('Correct answer!')
    congruency_result = checkCongruency(rndItem)
else:
    print('Incorrect answer')

Answer 2

由于函数内部的变量只能在 function 中使用，因此您可以将它们声明为全局变量，尽管这不是好的做法。

def checkCongruency(item):
    global correctCongruentAnswers #here
    global correctIncongruentAnswers #and here
    if item in lstCongruent:
        correctCongruentAnswers = 0
        correctCongruentAnswers += 1
        return correctCongruentAnswers
    elif item in lstIncongruent:
        correctIncongruentAnswers = 0
        correctIncongruentAnswers += 1
        return correctIncongruentAnswers