I am trying to use decorator to modify variable value in python with the following code
def config(func):
def new_function():
func()
print(lr)
return new_function
import ex
@ex.config
def config():
lr = 0.1
globals().update(locals())
config()
I would like to print out 0.1, but error with variable not defined was shown.
Is there anyway to achieve this without changing func_a?
In short, no.
What is happening here is func_a() is declaring and assigning lr as a local variable.
You can fix this by adding the global keyword:
lr = 0
def config(func):
def new_function(*args,**kwargs):
func(*args,**kwargs)
return new_function
@config
def func_a():
global lr
lr = 0.1
func_a()
print(lr)
But using the global keyword is annoying and can cause bugs if you forget it, so you might be better off returning:
lr = 0
def config(func):
def new_function(*args,**kwargs):
return func(*args,**kwargs)
return new_function
@config
def func_a():
return 0.1
lr = func_a()
print(lr)
You could put it in a class somehow like this:
# Make an empty class:
class Foo: pass
# Or if you want to initalize the variables:
class Foo:
def __init__(self):
lr = 0
f = Foo()
# The decorator doesn't make much of a difference
def func_a():
f.lr = 0.1
func_a()
print(f.lr)
Now, if you want to keep absolutely all the local variables that func_a defines, you could do this:
def func_a():
lr = 0.1
f.__dict__.update(locals())
func_a as it is. I am trying to replicate someone else's work and make adjustment based on it, the only part of the code I have is similar to func_a but with hundreds more variables. For more complete information, @config used to be @obj.config in their original code, but I don't think obj is a class.
lr must be a file-wide global variable? Because ideally you could put that (and he other hundreds) in a class or something. Here's another idea, with only slight modification to func_a(): stackoverflow.com/a/11543718/12465821'lr' is an local variable and you didn't save or return its value.So you just can get the value of global variable 'lr' in the first line and its value is 0.
