Updated sieve_of_eratosthenes.py

Edited according to unit test and changed the loop to list comprehension.

Author: vedangmehta

misc/sieve_of_eratosthenes.py

@@ -0,0 +1,29 @@
+"""
+
+Implementation of Sieve of Eratosthenes algorithm to generate all the primes upto N.
+
+Reference : https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
+
+Algorithm :
+* We have a list of numbers from 1 to N.
+* Initially, all the numbers are marked as primes.
+* We go to every prime number in the list (<= N ^ 1/2) and mark all the multiples of this prime number which are bigger than the number itself as non-primes.
+
+"""
+
+from math import sqrt,ceil
+
+def calculate_primes(n):
+    bool_array = [True] * (n+1)
+    bool_array[0] = False
+    bool_array[1] = False
+    upper_bound = ceil(sqrt(n))
+    for i in range(2,upper_bound):
+        if bool_array[i]:
+            for j in range(i*i,n+1,i):
+                bool_array[j] = False
+    prime_array = [i for i in range(n+1) if bool_array[i]]
+    return prime_array
+
+if __name__ == "__main__":
+    print(calculate_primes(50))