全局变量名称和不同函数(使用 Python)的问题

Question

我正在尝试使用函数编写不同困难的历史测验，但在"全局名称"方面遇到了一些麻烦。我试图纠正这一点，但似乎没有任何效果。

代码

片段代码为：

#Checking Answers
def checkEasyHistoryQuestions():
    score = 0
    if hisAnswer1E == 'B' or hisAnswer1E == 'b':
        score = score + 1
        print "Correct!"
    else:
        print "Incorrect!"
    if hisAnswer2E == 'A' or hisAnswer2E == 'a':
        score = score + 1
        print "Correct!"
    else:
        print "Incorrect!"
    if hisAnswer3E == 'B' or hisAnswer3E == 'b':
        score = score + 1
        print "Correct!"
    else:
        print "Incorrect!"
    print score
    print "n"
#History - Easy - QUESTIONS + INPUT 
def easyHistoryQuestions():
    print "n"
    print "1. What date did World War II start?"
    print "Is it:", "n", "A: 20th October 1939", "n", "B: 1st September 1939"
    hisAnswer1E = raw_input("Enter your choice: ")
    print "n"
    print "2. When did the Battle of Britain take place?"
    print "Is it: ", "n", "A: 10th July 1940 – 31st October 1940", "n", "B: 3rd July 1940- 2nd August 1940" 
    hisAnswer2E = raw_input("Enter your choice: ")
    print "n"
    print "3. Who succeeded Elizabeth I on the English throne?"
    print "Is it: ", "n", "A. Henry VIII", "n", "B. James VI"
    hisAnswer3E = raw_input("Enter your choice: ")
    print "n"
checkEasyHistoryQuestions()

我得到的错误是：

if hisAnswer1E == 'B' or hisAnswer1E == 'b':
NameError: global name 'hisAnswer1E' is not defined

我试图将他的 Answer1E 声明为函数内外的全局变量。

例如：

print "n"
print "1. What date did World War II start?"
print "Is it:", "n", "A: 20th October 1939", "n", "B: 1st September 1939"
global hisAnswer1E 
hisAnswer1E = raw_input("Enter your choice: ")
print "n"  

还有：

global hisAnswer1E 
#Checking Answers
def checkEasyHistoryQuestions():
    score = 0
    if hisAnswer1E == 'B' or hisAnswer1E == 'b':
        score = score + 1
        print "Correct!"
    else:
        print "Incorrect!"

似乎没有任何效果，我只是不断收到相同的错误。知道为什么吗？

Answer 1

声明

global hisAnswer1E的意思是"使用全局范围内的hisAnswer1E"。它实际上不会在全局范围内创建hisAnswer1E。

因此，要使用全局变量

，您应该首先在全局范围内创建一个变量，然后在函数中声明global hisAnswer1E

然而！！！

一条建议：不要使用全局变量。只是不要。

函数接受参数并返回值。这是在它们之间共享数据的正确机制。

在您的情况下，最简单的解决方案(即到目前为止对您所做的更改最少(是从easyHistoryQuestions返回答案并将它们传递给checkEasyHistoryQuestions，例如：

def checkEasyHistoryQuestions(hisAnswer1E, hisAnswer2E, hisAnswer3E):
    # <your code here>
def easyHistoryQuestions():
    # <your code here>
    return hisAnswer1E, hisAnswer2E, hisAnswer3E
hisAnswer1E, hisAnswer2E, hisAnswer3E = easyHistoryQuestions()
checkEasyHistoryQuestions(hisAnswer1E, hisAnswer2E, hisAnswer3E)

Answer 2

要在python中使用全局变量，我认为你应该在函数外部声明没有全局关键字的变量，然后在函数内部使用global关键字声明它。

x=5
def h():
   global x
   x=6
print(x)
h()
print(x)

此代码将打印

5
6

但是，全局变量通常是要避免的。