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

* Removed doctest call

* Removed 0 and 1 append to `fib_array`

* Moved fibonacci sequence logic into `calculate`

* Refactored `get` to generate missing numbers

* Renamed `fib_array` to `sequence`

* Renamed `number` to `index`

* Refactored `get` to only return sequence to `index`

* Moved main block into function

* Added documentation to `get`

* Added missing type hints

* Fixed doctest error in `get` docstring

* Moved calculate logic into get

* Reformatted with black

* Fixed wrong generation range

Author: citharus

dynamic_programming/fibonacci.py

@@ -5,61 +5,48 @@
 
 
 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 __init__(self) -> None:
+        self.sequence = [0, 1]
 
-    def get(self, sequence_no=None):
+    def get(self, index: int) -> list:
         """
-        >>> 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]
-        []
+        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]
         """
-        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")
+        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]
 
 
-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")
+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
 
-    import doctest
+        try:
+            index: int = int(prompt)
+        except ValueError:
+            print("Enter a number or 'exit'")
+            continue
 
-    doctest.testmod()
+        print(fibonacci.get(index))
+
+
+if __name__ == "__main__":
+    main()