CODEWITHSUNDEEP
python
user17067568
user17067568

Reputation: 1

python for loop to evaluate equation

I'm asked to write a function that should return the sum of the following series 1000 + 1/1**2 + 1/2**2 + 1/3**2 + 1/4**2 + ... + 1/n**2 for the given integer n. For example, for n = 0, the function should return 1000, for n = 1, the function should return 1001, for n = 2, the function should return 1001.25, for n = 3, the function should return 1001.3611111111111, etc.

I know for sure this needs to be done by for loops and range functions. Here's my code

if n<0:
        return None
if n>0 or n==0:
        for i in range(1,n-1):
            result=1000+1/(i**2)
            return result

But it keeps return None when n=o,1,2,3 I'm not sure how to fix this code...

Upvotes: 0

Views: 660

Answers (3)

j1-lee
j1-lee

Reputation: 13939

In each iteration, you are not updating result using the previous value of it. (Also you are returning result prematurely.) Update the variable by using result = result + 1 / (i ** 2), or equivalently, result += 1 / (i ** 2).

def foo(n):
    result = 1000
    for i in range(1, n+1):
        result += 1 / (i ** 2)
    return result

print(foo(0), foo(1), foo(2), foo(3)) # 1000 1001.0 1001.25 1001.3611111111111

Or, using (generator) comprehension,

def foo(n):
    return 1000 + sum(1 / (i ** 2) for i in range(1, n + 1))

Upvotes: 2

Saurabh Sawhney
Saurabh Sawhney

Reputation: 56

First, you can only return from within a function, but your code has no function definition included - maybe you forgot. Second, if this code is part of a function, the first iteration of the loop will throw you out of the function as soon as it hits return, so this function, if implemented, will not complete the intended loop iterations. Since this is a homework question, I will not complete the code, but I hope this gives you a start.

Upvotes: 0

000
000

Reputation: 230

You don't need any if statements. What you're doing right now is calculating result, then immediately returning the result on step 1.

result = 1000
for i in range(1,n+1):
    result += 1/(i**2)
return result

Comment if anything doesn't make sense

Upvotes: 0

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