Question

PYTHON PROBLEM: TASKED TO FIND THE FLAW WITH THE FOLLOWING CODE:

from itertools import count

def take_e(n, gen):

    return [elem for (i, elem) in enumerate(gen) if i < n]

def take_zc(n, gen):

    return [elem for (i, elem) in zip(count(), gen) if i < n]

FIBONACCI UNBOUNDED:

def fibonacci_unbounded():

    """

    Unbounded Fibonacci numbers generator

    """

    (a, b) = (0, 1)

    while True:

        # return a

        yield a

        (a, b) = (b, a + b)

SUPPOSED TO RUN THIS TO ASSIST WITH FINDING THE FLAW:

take_e(5, fibonacci_unbounded())

Answer 1

The code under function fibonacci_unbounded is 100% correct.It will create and return a infinite fibonacci generator object.

FLAW:-

return [elem for (i, elem) in enumerate(gen()) if i < n]

          This is a normal list comprehension statment. The wrong   here is that a termination statement is not provided .

NO ,i<n will not terminate and return the list. It is a check condition for the values which has to inserted in list . It is not responsible for the termination and returning of the list. i<n will keep checking for the next element till infinity .

Same problem in the take_zc function

                       Thats why this code is not working.

REMEDY:- Replace your take_e function with this

             def take_e(n, gen):
                    l1 = []
                    for i,elem in enumerate(gen):
                          l1.append(elem)
                          if i>=n:return l1

Attaching the full code with output:-

     

NOTE :- Since , you haven't asked for take_zc function and I am not sure what this function want to achieve .It is difficult for me to write an alternative solution for that function.