Factors of a number (#1493)

* Factors of a number

* Update factors.py

* Fix mypy issue in basic_maths.py

* Fix mypy error in perceptron.py

* def primes(max: int) -> List[int]:

* Update binomial_heap.py

* Add a space

* Remove a space

* Add a space

maths/basic_maths.py

@@ -67,10 +67,8 @@ def euler_phi(n: int) -> int:
     >>> euler_phi(100)
     40
     """
-    l = prime_factors(n)
-    l = set(l)
     s = n
-    for x in l:
+    for x in set(prime_factors(n)):
         s *= (x - 1) / x
     return int(s)
 

maths/factors.py

@@ -0,0 +1,18 @@
+def factors_of_a_number(num: int) -> list:
+    """
+    >>> factors_of_a_number(1)
+    [1]
+    >>> factors_of_a_number(5)
+    [1, 5]
+    >>> factors_of_a_number(24)
+    [1, 2, 3, 4, 6, 8, 12, 24]
+    >>> factors_of_a_number(-24)
+    []
+    """
+    return [i for i in range(1, num + 1) if num % i == 0]
+
+
+if __name__ == "__main__":
+    num = int(input("Enter a number to find its factors: "))
+    factors = factors_of_a_number(num)
+    print(f"{num} has {len(factors)} factors: {', '.join(str(f) for f in factors)}")

maths/prime_numbers.py

@@ -1,9 +1,9 @@
-"""Prime numbers calculation."""
+from typing import List
 
 
-def primes(max: int) -> int:
+def primes(max: int) -> List[int]:
     """
-    Return a list of all primes up to max.
+    Return a list of all primes numbers up to max.
     >>> primes(10)
     [2, 3, 5, 7]
     >>> primes(11)