"""
This is a pure Python implementation of Dynamic Programming solution to the fibonacci
sequence problem.
"""


class Fibonacci:
    def __init__(self, N=None):
        self.fib_array = []
        if N:
            N = int(N)
            self.fib_array.append(0)
            self.fib_array.append(1)
            for i in range(2, N + 1):
                self.fib_array.append(self.fib_array[i - 1] + self.fib_array[i - 2])
        elif N == 0:
            self.fib_array.append(0)
        print(self.fib_array)

    def get(self, sequence_no=None):
        """
        >>> Fibonacci(5).get(3)
        [0, 1, 1, 2, 3, 5]
        [0, 1, 1, 2]
        >>> Fibonacci(5).get(6)
        [0, 1, 1, 2, 3, 5]
        Out of bound.
        >>> Fibonacci(5).get(-1)
        [0, 1, 1, 2, 3, 5]
        []
        """
        if sequence_no is not None:
            if sequence_no < len(self.fib_array):
                return print(self.fib_array[: sequence_no + 1])
            else:
                print("Out of bound.")
        else:
            print("Please specify a value")


if __name__ == "__main__":
    print("\n********* Fibonacci Series Using Dynamic Programming ************\n")
    print("\n Enter the upper limit for the fibonacci sequence: ", end="")
    try:
        N = int(input().strip())
        fib = Fibonacci(N)
        print(
            "\n********* Enter different values to get the corresponding fibonacci "
            "sequence, enter any negative number to exit. ************\n"
        )
        while True:
            try:
                i = int(input("Enter value: ").strip())
                if i < 0:
                    print("\n********* Good Bye!! ************\n")
                    break
                fib.get(i)
            except NameError:
                print("\nInvalid input, please try again.")
    except NameError:
        print("\n********* Invalid input, good bye!! ************\n")

    import doctest

    doctest.testmod()

"""
This is a pure Python implementation of Dynamic Programming solution to the fibonacci
sequence problem.
"""


class Fibonacci:
    def __init__(self) -> None:
        self.sequence = [0, 1]

    def get(self, index: int) -> list:
        """
        Get the Fibonacci number of `index`. If the number does not exist,
        calculate all missing numbers leading up to the number of `index`.

        >>> Fibonacci().get(10)
        [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
        >>> Fibonacci().get(5)
        [0, 1, 1, 2, 3]
        """
        difference = index - (len(self.sequence) - 2)
        if difference >= 1:
            for _ in range(difference):
                self.sequence.append(self.sequence[-1] + self.sequence[-2])
        return self.sequence[:index]


def main():
    print(
        "Fibonacci Series Using Dynamic Programming\n",
        "Enter the index of the Fibonacci number you want to calculate ",
        "in the prompt below. (To exit enter exit or Ctrl-C)\n",
        sep="",
    )
    fibonacci = Fibonacci()

    while True:
        prompt: str = input(">> ")
        if prompt in {"exit", "quit"}:
            break

        try:
            index: int = int(prompt)
        except ValueError:
            print("Enter a number or 'exit'")
            continue

        print(fibonacci.get(index))


if __name__ == "__main__":
    main()

Rewrite fibonacci.py (#5665) (#5677)