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I want to write a decorator that will compute runtime of function that compute fibonachi number of 5(fib(5)) 10 times and will print a medium runtime value. But my decorator returns an error. How to fix this problem?

import functools import time def trace(times): def cache(func): @functools.wraps(func) def wrapper(*args, **kwargs): total = 0 for i in range(times): start = time.time() func(*args, **kwargs) end = time.time() total += (end - start) print('Medium value is {}'.format(total / times)) return func return wrapper return cache @trace(times=10) def fib(num): if num < 2: return num return fib(num - 1) + fib(num - 2) fib(5)
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First, instead of returning func in the wrapper return the result of it.

We have to make sure the tracing only happens for the first call to fib and none of the recursive calls. Let's use a boolean traced argument:

import functools import time def trace(times): def cache(func): @functools.wraps(func) def wrapper(*args, traced=True, **kwargs): if not traced: return func(*args, **kwargs) total = 0 for i in range(times): start = time.time() result = func(*args, **kwargs) end = time.time() total += (end - start) print(f'run {i}, time is {total}') print(f'Mean value is {total / times}') return result return wrapper return cache @trace(times=10) def fib(num, traced=True): if num < 2: return num return fib(num - 1, traced=False) + fib(num - 2, traced=False) fib(5)

traced is True by default so any call to fib(n) will be traced (no need for user to be aware of the traced argument). However the recursive calls all have traced=False therefore they don't trigger the loop in the decorator.

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8 Comments

but that program compute medium value for all of fib(5) - fib(5), fib(4), ..., fib(1). But I want just to compute medium value only for fib(5) 10 times. I want to print 10 values of fib(5) runtime
That's what I asked you in the comment above. Give me a moment...
Do you have to do it with decorators?
yes. with decorator
The difference between your code and my code is only 'traced', right?
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