This notebook was prepared by [Thunder Shiviah]( Source and license info is on [GitHub](

Solution Notebook

Problem: Implement list_primes(n), which returns a list of primes up to n (inclusive).


  • Does list_primes do anything else?
    • No

Test Cases

  • list_primes(1) -> [] # 1 is not prime.
  • list_primes(2) -> [2]
  • list_primes(12) -> [2, 3, 5, 7 , 11]


Primes are numbers which are only divisible by 1 and themselves.

5 is a prime since it can only be divided by itself and 1. 9 is not a prime since it can be divided by 3 (3*3 = 9). 1 is not a prime for reasons that only mathematicians care about.

To check if a number is prime, we can implement a basic algorithm, namely: check if a given number can be divided by any numbers smaller than the given number (note: you really only need to test numbers up to the square root of a given number, but it doesn't really matter for this assignment).


In [98]:
def list_primes(n):
    primes = []
    for p in range(2, n + 1): # we add a '+ 1' to be inclusive.
        for num in range(2, p):
            if p % num == 0:
    return primes

Unit Test

In [100]:


In [101]:
%run -i

Success: test_list_primes

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