[英]Global variable Issues with different functions (using Python)
I am trying to create a program that allows me to use my list 'users' in a different function in the program. 我正在尝试创建一个程序,允许我在程序的其他功能中使用列表“用户”。 I have tried parameters, declaring it 'global' (although I've been told it's bad practice to do that) and I've tried researching 'class' and implementing it all to no avail.
我尝试了参数,将其声明为“全局”(尽管有人告诉我这样做是不好的做法),并且我尝试研究“类”并将其全部实施都无济于事。 I have also tried putting users into a text file and then reading from it but it's a nuisance as I need it to be in a list.
我还尝试将用户放入文本文件中,然后从中读取内容,但这很麻烦,因为我需要将其包含在列表中。 Here is my code:
这是我的代码:
def register():
global username
username = raw_input("Enter a username: ").lower()
firstName = raw_input("Enter your first name: ").lower()
surname = raw_input("Enter your surname: ").lower()
age = raw_input("Enter your age: ")
yearGroup = raw_input("Enter your year group: ")
users =[[firstName, surname, age, yearGroup]]
def resultsFunction():
score = 5
results = [[score, username]]
results.extend(users)
I have tried: 我努力了:
def register():
global username
username = raw_input("Enter a username: ").lower()
firstName = raw_input("Enter your first name: ").lower()
surname = raw_input("Enter your surname: ").lower()
age = raw_input("Enter your age: ")
yearGroup = raw_input("Enter your year group: ")
global users
users =[[firstName, surname, age, yearGroup]]
It throws up the error: 它引发错误:
results.extend(userDetails)
NameError: global name 'userDetails' is not defined
The strange thing is, after declaring username 'global' (yes, I know I shouldn't, but it worked), I was able to use the username in the function but when I tried it with the other variables, eg firstName so I could try to create the list simply in the 'resultsFunction' it wouldn't work. 奇怪的是,在声明用户名'global'之后(是的,我知道我不应该,但是它起作用了),我能够在函数中使用用户名,但是当我尝试使用其他变量(例如firstName)时,可以尝试仅在“ resultsFunction”中创建列表,但无法使用。
The register function does not get run all the time if the user decides not to register but I can't change that as I do not want the user to have to always put in their details. 如果用户决定不进行注册,则注册功能不会一直运行,但是我无法更改它,因为我不希望用户必须始终输入其详细信息。
I am so confused and have tried everything I know. 我很困惑,尝试了我所知道的一切。 I came here as a last resort so I hope that someone can help and that maybe this question can help others having the same difficulties with the local and global variables scopes.
我来这里是最后的选择,所以我希望有人可以提供帮助,也许这个问题可以帮助其他在局部和全局变量范围上遇到相同困难的人。
Write global users
inside the function to change values in the users
variable. 在函数内编写
global users
以更改users
变量中的值。 Otherwise you can only read it but not change the value inside it. 否则,您只能读取它,而不能更改其中的值。
lis = []
def a():
lis = [1,2]
a()
print(lis)
will print []
将打印
[]
where as : 如:
lis = []
def a():
global lis
lis = [1,2]
a()
print(lis)
will print [1,2]
将打印
[1,2]
With reference to your program as per my understanding.. this might help.. 根据我的理解,请参考您的程序。这可能会有所帮助。
username = ''
user = []
def register():
global username
global users
username = input("Enter a username: ").lower()
firstName = input("Enter your first name: ").lower()
surname = input("Enter your surname: ").lower()
age = input("Enter your age: ")
yearGroup = input("Enter your year group: ")
users =[[firstName, surname, age, yearGroup]]
def resultsFunction():
score = 5
results = [[score, username]]
results.extend(users)
print(results)
register()
resultsFunction()
will output :- 将输出:-
Enter a username: Foo
Enter your first name: Bar
Enter your surname: Baz
Enter your age: 00
Enter your year group: 00
[[5, 'foo'], ['bar', 'baz', '00', '00']]
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