Added algorithm to compute prime numbers less than x

allalgorithms/math/__init__.py

@@ -0,0 +1 @@
+from .max_numbers import find_max

allalgorithms/math/prime_numbers.py

@@ -0,0 +1,31 @@
+# -*- coding: UTF-8 -*-
+#
+# Numeric Algorithms
+# The All ▲lgorithms library for python
+#
+# Contributed by: Rodolfo
+# Github: @RQuispeC
+#
+import math
+
+SIEVE_LIMIT = 1000000
+
+def sieve(n):
+    prime = [True]*(n+1)
+    prime[0] = False
+    prime[1] = False
+    for i in range(2,int(math.sqrt(n)) + 1):
+        if prime[i]:
+            for j in range(i*i, n+1, i):
+                prime[j] = False
+    return prime
+
+def prime_lower(n):
+    if n < 1 or n > SIEVE_LIMIT:
+        return []
+    prime = sieve(n)
+    ans = []
+    for i in range(n+1):
+        if prime[i]:
+            ans.append(i)
+    return ans

docs/math/prime-numbers.md

@@ -0,0 +1,34 @@
+# Prime Numbers
+
+Using prime numbers is common in many problems. We implement various algorithms using them.
+
+## Install
+
+```
+pip install allalgorithms
+```
+
+## Usage
+
+```py
+from allalgorithms.math import prime_lower
+
+print(prime_lower(18))
+# -> [2, 3, 5, 7, 11, 13, 17]
+
+print(prime_lower(-1))
+# -> []
+
+print(prime_lower(1000001))
+# -> []
+```
+
+## API
+
+### prime_lower(query)
+
+> Return array of prime numbers lower than `query`, `query` must be lower than `10e6` to avoid memory problems.
+
+##### Params:
+
+- `query`: superior limit for the array of prime number

tests/test_numeric.py → tests/test_math.py

@@ -1,7 +1,8 @@
 import unittest
 
-from allalgorithms.numeric import find_max
-
+from allalgorithms.math import (
+    find_max
+)
 
 class TestMax(unittest.TestCase):