Category : closures

I’m quite new to Python, but I’m trying to implement my "Line file reader" and I came across an error that I don’t understand why it wouldn’t work. UnboundLocalError: local variable ‘i’ referenced before assignment The generator can see the file variable in the closure just fine, why can’t it see i? import contextlib @contextlib.contextmanager ..

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I have a function factory(takes n as variable initialized to zero) with two inner functions current(returns the value of n) and counter(which returns the value n+1). def factory(n=0): def counter(): return n+1 return counter def current(): return n return current f_current,f_counter=factory(int(input())) I’m getting TypeError: cannot unpack non-iterable function object Source: Python..

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I am trying to store lambda functions in a python dictionary. It seems that the loop overwrites all of the data stored in the dictionary with the last lambda. For example: example_dict = {} for i in range(5): example_dict[i] = lambda x: x + i for key, func in example_dict.items(): print(key, func(10)) Should output 0 ..

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Was experimenting with applying memoization decorator to recursive functions using standard python @decorator notation, which worked beautifully. According to much of the documentation I’ve read, these code examples are supposed to be equivalent: # letting python decorator mechanism take care of wrapping your function with the decorator function @decorator def func(): . . . print(func(arg)) ..

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Can someone please help me understand how the below code works? The intent of this code is to take in two elements, make them a pair, Function car returns the first element and Function cdr returns the last element. I am having trouble with understanding how exactly closure works. I understand how lambda works but ..

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