UnboundLocalError: local variable 'Y_best' referenced before assignment
时间: 2023-10-23 07:15:08 浏览: 41
This error occurs when a local variable is referenced before it is assigned a value within a function.
For example:
```
def find_best_y():
if some_condition:
Y_best = 10
print(Y_best)
```
In the above code, if the condition is not met, the variable `Y_best` will not be assigned a value but it's being referenced in the `print` statement. This will raise an `UnboundLocalError` because the variable has not been assigned a value yet.
To fix this error, make sure that all local variables are assigned values before they are referenced in the function. One way to do this is to initialize the variable with a default value before the conditional statements:
```
def find_best_y():
Y_best = None
if some_condition:
Y_best = 10
print(Y_best)
```
In the above code, `Y_best` is initialized with `None` before the conditional statement. This ensures that the variable is always assigned a value before it's referenced within the function.