UnboundLocalError:在赋值前引用的局部变量r[复制]

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I'm having an issue with variable and function. Here is a simple code:

我有一个变量和函数的问题。这里有一个简单的代码:

r = 0
list = ['apple','lime','orange']
def list_list(x):
    for i in x:
        r +=1
        print r
list_list(list)

Error:

UnboundLocalError: local variable 'r' referenced before assignment

I know it must be something simple. I started to do my script using functions instead straight code.

我知道这一定很简单。我开始使用函数而不是直接代码来执行脚本。

You should rewrite your function to take r as an argument if you want to define it outside of your function:

如果你想把r定义在函数之外，你应该重写你的函数把r当作一个参数:

def my_func(some_list, r=0):
    # do some stuff

Basically, you have a problem with scope. If you need r outside of the function, just return it's value in a tuple:

基本上，你有一个范围的问题。如果你需要函数外的r，只需返回一个元组中的值:

def my_func(some_list, r=0):
    # do some stuff

    return new_list, r

my_list = [1,2,3,4,5]
different_list, my_outside_r = my_func(some_list, 0)

The r within the function isn't the same as the one outside the function, so it hasn't been set yet.

函数内的r与函数外面的r不一样，所以它还没有被设置。

You shoudld put r = 0 inside the function. But if you want the length of the list just use len(list)

你应该把r = 0放在函数里面。但是如果你想要列表的长度就用len(list)

Also try to avoid naming variables same as builtin names like list.

也要尽量避免使用与构建名称相同的命名变量。