使其可用的功能外变量

-1

def Payment(): 
    print('The cost for''is 1£') 
    print('Please insert coin') 
    credit = float(input()) 
    while credit < 1: 
     print('Your credit now is', credit,'£') 
     print('You still need to add other',-credit+1,'cent') 
     newcredit = float(input()) 
     credit = newcredit + credit 
Payment() 
print(credit)

现在我需要的是能够同时在主代码后读变量“信用”，但我得到的错误

NameError: name 'credit' is not defined

如何从函数Payment中提取变量credit以在主程序中使用？

来源

2017-06-01 Giuseppe Faro

您可以尝试使用'global credit'作为全局变量传递它。 –

返回它作为功能结果：

def Payment(): 

    print('The cost for''is 1£') 
    print('Please insert coin') 
    credit = float(input()) 

    while credit < 1: 
     print('Your credit now is', credit,'£') 
     print('You still need to add other',-credit+1,'cent') 
     newcredit = float(input()) 
     credit = newcredit + credit 

    return credit 


balance = Payment() 
print(balance)

来源

2017-06-01 00:07:12 Prune

还可以声明信用为全局变量，虽然这不是真正的好作风 –

我清楚这一点 - 无论它是可能的，而且它的不良作风。教他们路径...... :-) – Prune

你应该只从return像@Prune功能的变量显示。

，但如果你硬是想把它当作global变量，你必须定义它的功能之外，它global credit你的函数内部（即会告诉Python的，应该改变功能范围之外的变量）：

credit = 0 

def Payment(): 
    global credit 
    credit = float(input()) 
    while credit < 1: 
     newcredit = float(input()) 
     credit = newcredit + credit 
Payment() 
print(credit)

但return的替代方案好得多，我只是提出它，因为它在评论（两次）中提到。

来源

2017-06-01 00:17:32 MSeifert

除了返回贷方之外，您可以将该值存储到另一个变量中并以此方式处理。如果您需要进一步修改信用变量。 new_variable = credit print(new_variable)

来源

2017-06-01 00:53:44 nuji

这比你想象的更容易。
首先，分配一个名为credit的变量（在函数外）。这不会与任何功能交互。

credit = 0

让你的函数除了增加一个参数和增加一个return语句。

def Payment(currentcredit): 
     ... 
     return currentcredit - credit #lose credit after payment

最后，

credit = Payment(credit)

最后的代码是

credit = 100 
def Payment(currentcredit): 
    print('The cost for''is 1£') 
    print('Please insert a coin') 
    credit = float(input()) 
    while credit < 1: 
     print('Your credit is now', currentcredit,'£') 
     print('You still need to add another',-credit+1,'cents!') 
     newcredit = float(input()) 
     credit = newcredit + credit 
    return currentcredit - credit 
credit = Payment(credit) 
print(credit)

输出

CON: The cost for ' ' is 1£
CON: Please insert a coin
ME: 0.5
CON: Your credit is now 100£
CON: You still need to add another 0.5 cents!
ME: 49.5
Variable "credit" updated to Payment(100) => 50
CON: 50

[50信用= 100信用减去50信用损失] 工程就像一个魅力。

来源

2017-06-01 03:14:12 Christian

使其可用的功能外变量

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