Coding Fibonacci in python. Got errors

Question

There is a assigment I am doing for Beginners in AI and Python.

Create a Class NewInt that inherits from int. It should have an Instance Method is_fibonacci () that returns True if the number is a Fibonacci number, False if not. Generate a list with NewInt from 0 to 1000. Then create a List Comprehension that only retains the numbers that are Fibonacci using the class and instance method you created.

[0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987] #Expected output for task

I made this code for the task

import math

class NewInt(int):
   
    def is_Perfect_Square(x):
        s = int(math.sqrt(x))
        return s*s == x

    def is_fibonacci(n):

        return is_Perfect_Square(5*n*n + 4) or is_Perfect_Square(5*n*n - 4)

    fibonacci_List = [i for i in range(0,1000)if NewInt().is_fibonacci(i)]
    print(fibonacci_List)

It worked few hours ago, but i get errors like this:

TypeError                                 Traceback (most recent call last)
<ipython-input-8-377e0f9b7814> in <module>
      1 import math
      2 
----> 3 class NewInt(int):
      4 
      5     def is_Perfect_Square(x):

<ipython-input-8-377e0f9b7814> in NewInt()
     11         return is_Perfect_Square(5*n*n + 4) or is_Perfect_Square(5*n*n - 4)
     12 
---> 13     fibonacci_List = [i for i in range(0,1000)if NewInt().is_fibonacci(i)]
     14     print(fibonacci_List)

<ipython-input-8-377e0f9b7814> in <listcomp>(.0)
     11         return is_Perfect_Square(5*n*n + 4) or is_Perfect_Square(5*n*n - 4)
     12 
---> 13     fibonacci_List = [i for i in range(0,1000)if NewInt().is_fibonacci(i)]
     14     print(fibonacci_List)

TypeError: is_fibonacci() takes 1 positional argument but 2 were given

Can someone help me point out my mistakes? I am new to Python.

You are somewhat confusing instance and static methods here. You can try NewInt.is_fibonacci(i), but the whole NewInt class does not make all that much sense. Also, why not just generate the fibonacci sequence instead of testing each number whether it is a fibonacci number? — tobias_k
– tobias_k, Commented Sep 6, 2021 at 18:21
Your class methods need a first argument of self to contain the instance reference. — RufusVS
– RufusVS, Commented Sep 7, 2021 at 2:12

Balaji · Accepted Answer · 2021-09-06 19:48:21Z

2

This is pythons OOP concept

NewInt().is_fibonacci(i)
When the above method is called python internally does this

NewInt().is_fibonacci(self, i)
self refers to the object that invoked the method in this case NewInt()
But in the class definition the method is defined for only one parameter hence

TypeError: is_fibonacci() takes 1 positional argument but 2 were given

import math

class NewInt(int):

    def is_Perfect_Square(self, x):
        s = int(math.sqrt(x))
        return s*s == x

    def is_fibonacci(self, n):
        return self.is_Perfect_Square(5*n*n + 4) or self.is_Perfect_Square(5*n*n - 4)

fibonacci_List = [i for i in range(0,1000)if NewInt().is_fibonacci(i)]
print(fibonacci_List)

answered Sep 6, 2021 at 19:48

Balaji

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Comments

Nothing special · Accepted Answer · 2021-09-06 19:25:06Z

1

import math


class NewInt(int):

    # In my opinion you should make a constructor
    def __init__(self, number):
        # Declare the attributes
        self.number = number

    def is_Perfect_Square(self):
        # Use that attribute which u have initialised already.
        x = self.number
        s = int(math.sqrt(x))
        return s * s == x

    def is_fibonacci(self):
        n = self.number
        # Create an instance of your class each time u wanna access a method
        # e.g. NewInt(1234) creates an instant of the class NewInt. When you do this, u invoke the init method and that number attribute is intialised.
        return NewInt(5*n*n + 4).is_Perfect_Square() or NewInt(5 * n * n - 4).is_Perfect_Square()


fibonacci_List = [i for i in range(0, 1000) if NewInt(i).is_fibonacci()]

print(fibonacci_List)

Output:

[0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987]

If you are always taking the value in the formal parameter of your function, it doesn't make sense to have a class.

edited Sep 6, 2021 at 19:25

answered Sep 6, 2021 at 18:52

Nothing special

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1 Comment

Nicholai Mørch Rindarøy Over a year ago

Thanks for the feedback Nothing special. It's nice to get advice. I cool to see there is severals way to solve this problem. :)

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