UnboundLocalError: local variable 'back2' referenced before assignment
时间: 2023-10-23 17:13:28 浏览: 45
This error occurs when you try to access a local variable before assigning a value to it. In other words, the variable has not been defined yet in the current scope.
Here is an example:
```
def my_function():
print(back2)
back2 = "Hello"
my_function()
```
In this example, we are trying to print the value of `back2` before assigning a value to it. This will result in an `UnboundLocalError` because Python does not know what the value of `back2` is yet.
To fix this error, you need to make sure that the variable is defined before you try to access it. Here's an updated version of the code that fixes the error:
```
def my_function():
back2 = "Hello"
print(back2)
my_function()
```
In this example, we define the variable `back2` before we try to print its value. Now the code will run without errors.