TheAlgorithms · cclauss · Oct 21, 2020 · Oct 21, 2020 · Oct 21, 2020
diff --git a/DIRECTORY.md b/DIRECTORY.md
@@ -323,6 +323,10 @@
   * [Sdbm](https://github.com/TheAlgorithms/Python/blob/master/hashes/sdbm.py)
   * [Sha1](https://github.com/TheAlgorithms/Python/blob/master/hashes/sha1.py)
 
+## Knapsack
+  * [Knapsack](https://github.com/TheAlgorithms/Python/blob/master/knapsack/knapsack.py)
+  * [Test Knapsack](https://github.com/TheAlgorithms/Python/blob/master/knapsack/test_knapsack.py)
+
 ## Linear Algebra
   * Src
     * [Lib](https://github.com/TheAlgorithms/Python/blob/master/linear_algebra/src/lib.py)
@@ -502,6 +506,7 @@
   * [Magicdiamondpattern](https://github.com/TheAlgorithms/Python/blob/master/other/magicdiamondpattern.py)
   * [Markov Chain](https://github.com/TheAlgorithms/Python/blob/master/other/markov_chain.py)
   * [Max Sum Sliding Window](https://github.com/TheAlgorithms/Python/blob/master/other/max_sum_sliding_window.py)
+  * [Median Of Two Arrays](https://github.com/TheAlgorithms/Python/blob/master/other/median_of_two_arrays.py)
   * [Nested Brackets](https://github.com/TheAlgorithms/Python/blob/master/other/nested_brackets.py)
   * [Palindrome](https://github.com/TheAlgorithms/Python/blob/master/other/palindrome.py)
   * [Password Generator](https://github.com/TheAlgorithms/Python/blob/master/other/password_generator.py)

diff --git a/ciphers/simple_substitution_cipher.py b/ciphers/simple_substitution_cipher.py
@@ -18,7 +18,7 @@ def main():
         mode = "decrypt"
         translated = decryptMessage(key, message)
 
-    print("\n{}ion: \n{}".format(mode.title(), translated))
+    print(f"\n{mode.title()}ion: \n{translated}")
 
 
 def checkValidKey(key: str) -> None:

diff --git a/ciphers/xor_cipher.py b/ciphers/xor_cipher.py
@@ -141,14 +141,14 @@ def encrypt_file(self, file: str, key: int = 0) -> bool:
         assert isinstance(file, str) and isinstance(key, int)
 
         try:
-            with open(file, "r") as fin:
+            with open(file) as fin:
                 with open("encrypt.out", "w+") as fout:
 
                     # actual encrypt-process
                     for line in fin:
                         fout.write(self.encrypt_string(line, key))
 
-        except IOError:
+        except OSError:
             return False
 
         return True
@@ -166,14 +166,14 @@ def decrypt_file(self, file: str, key: int) -> bool:
         assert isinstance(file, str) and isinstance(key, int)
 
         try:
-            with open(file, "r") as fin:
+            with open(file) as fin:
                 with open("decrypt.out", "w+") as fout:
 
                     # actual encrypt-process
                     for line in fin:
                         fout.write(self.decrypt_string(line, key))
 
-        except IOError:
+        except OSError:
             return False
 
         return True

diff --git a/compression/lempel_ziv.py b/compression/lempel_ziv.py
@@ -17,10 +17,10 @@ def read_file_binary(file_path: str) -> str:
         with open(file_path, "rb") as binary_file:
             data = binary_file.read()
         for dat in data:
-            curr_byte = "{0:08b}".format(dat)
+            curr_byte = f"{dat:08b}"
             result += curr_byte
         return result
-    except IOError:
+    except OSError:
         print("File not accessible")
         sys.exit()
 
@@ -105,7 +105,7 @@ def write_file_binary(file_path: str, to_write: str) -> None:
 
             for elem in result_byte_array:
                 opened_file.write(int(elem, 2).to_bytes(1, byteorder="big"))
-    except IOError:
+    except OSError:
         print("File not accessible")
         sys.exit()
 

diff --git a/compression/lempel_ziv_decompress.py b/compression/lempel_ziv_decompress.py
@@ -16,10 +16,10 @@ def read_file_binary(file_path: str) -> str:
         with open(file_path, "rb") as binary_file:
             data = binary_file.read()
         for dat in data:
-            curr_byte = "{0:08b}".format(dat)
+            curr_byte = f"{dat:08b}"
             result += curr_byte
         return result
-    except IOError:
+    except OSError:
         print("File not accessible")
         sys.exit()
 
@@ -76,7 +76,7 @@ def write_file_binary(file_path: str, to_write: str) -> None:
 
             for elem in result_byte_array[:-1]:
                 opened_file.write(int(elem, 2).to_bytes(1, byteorder="big"))
-    except IOError:
+    except OSError:
         print("File not accessible")
         sys.exit()
 

diff --git a/data_structures/binary_tree/segment_tree_other.py b/data_structures/binary_tree/segment_tree_other.py
@@ -7,7 +7,7 @@
 from queue import Queue
 
 
-class SegmentTreeNode(object):
+class SegmentTreeNode:
     def __init__(self, start, end, val, left=None, right=None):
         self.start = start
         self.end = end
@@ -17,10 +17,10 @@ def __init__(self, start, end, val, left=None, right=None):
         self.right = right
 
     def __str__(self):
-        return "val: %s, start: %s, end: %s" % (self.val, self.start, self.end)
+        return f"val: {self.val}, start: {self.start}, end: {self.end}"
 
 
-class SegmentTree(object):
+class SegmentTree:
     """
     >>> import operator
     >>> num_arr = SegmentTree([2, 1, 5, 3, 4], operator.add)

diff --git a/data_structures/heap/heap.py b/data_structures/heap/heap.py
@@ -1,7 +1,7 @@
 #!/usr/bin/python3
 
 
-class Heap(object):
+class Heap:
     """
     >>> unsorted = [103, 9, 1, 7, 11, 15, 25, 201, 209, 107, 5]
     >>> h = Heap()

diff --git a/data_structures/linked_list/deque_doubly.py b/data_structures/linked_list/deque_doubly.py
@@ -20,7 +20,7 @@ def __init__(self, link_p, element, link_n):
             self._next = link_n
 
         def has_next_and_prev(self):
-            return " Prev -> {0}, Next -> {1}".format(
+            return " Prev -> {}, Next -> {}".format(
                 self._prev is not None, self._next is not None
             )
 

diff --git a/graphs/minimum_spanning_tree_boruvka.py b/graphs/minimum_spanning_tree_boruvka.py
@@ -99,7 +99,7 @@ def build(vertices=None, edges=None):
             g.add_edge(*edge)
         return g
 
-    class UnionFind(object):
+    class UnionFind:
         """
         Disjoint set Union and Find for Boruvka's algorithm
         """

diff --git a/machine_learning/astar.py b/machine_learning/astar.py
@@ -13,7 +13,7 @@
 import numpy as np
 
 
-class Cell(object):
+class Cell:
     """
     Class cell represents a cell in the world which have the property
     position : The position of the represented by  tupleof x and y
@@ -45,7 +45,7 @@ def showcell(self):
         print(self.position)
 
 
-class Gridworld(object):
+class Gridworld:
     """
     Gridworld class represents the  external world here a grid M*M
     matrix

diff --git a/machine_learning/k_means_clust.py b/machine_learning/k_means_clust.py
@@ -251,7 +251,7 @@ def ReportGenerator(
                     lambda x: np.mean(
                         np.nan_to_num(
                             sorted(x)[
-                                round((len(x) * 25 / 100)) : round(len(x) * 75 / 100)
+                                round(len(x) * 25 / 100) : round(len(x) * 75 / 100)
                             ]
                         )
                     ),

@@ -68,7 +68,7 @@ def calculate_prob(text: str) -> None:
             my_fir_sum += prob * math.log2(prob)  # entropy formula.
 
     # print entropy
-    print("{0:.1f}".format(round(-1 * my_fir_sum)))
+    print("{:.1f}".format(round(-1 * my_fir_sum)))
 
     # two len string
     all_sum = sum(two_char_strings.values())
@@ -83,10 +83,10 @@ def calculate_prob(text: str) -> None:
                 my_sec_sum += prob * math.log2(prob)
 
     # print second entropy
-    print("{0:.1f}".format(round(-1 * my_sec_sum)))
+    print("{:.1f}".format(round(-1 * my_sec_sum)))
 
     # print the difference between them
-    print("{0:.1f}".format(round(((-1 * my_sec_sum) - (-1 * my_fir_sum)))))
+    print("{:.1f}".format(round((-1 * my_sec_sum) - (-1 * my_fir_sum))))
 
 
 def analyze_text(text: str) -> tuple[dict, dict]:

@@ -62,5 +62,5 @@ def f(x):
     i = 10
     while i <= 100000:
         area = trapezoidal_area(f, -5, 5, i)
-        print("with {} steps: {}".format(i, area))
+        print(f"with {i} steps: {area}")
         i *= 10
@@ -17,7 +17,7 @@ def solution():
     '5537376230'
     """
     file_path = os.path.join(os.path.dirname(__file__), "num.txt")
-    with open(file_path, "r") as file_hand:
+    with open(file_path) as file_hand:
         return str(sum([int(line) for line in file_hand]))[:10]
 
 

@@ -41,7 +41,7 @@ def solution():
     script_dir = os.path.dirname(os.path.realpath(__file__))
     triangle = os.path.join(script_dir, "triangle.txt")
 
-    with open(triangle, "r") as f:
+    with open(triangle) as f:
         triangle = f.readlines()
 
     a = [[int(y) for y in x.rstrip("\r\n").split(" ")] for x in triangle]

@@ -30,7 +30,7 @@ def solution():
     wordsFilePath = os.path.join(script_dir, "words.txt")
 
     words = ""
-    with open(wordsFilePath, "r") as f:
+    with open(wordsFilePath) as f:
         words = f.readline()
 
     words = list(map(lambda word: word.strip('"'), words.strip("\r\n").split(",")))

@@ -114,7 +114,7 @@ def solution():
                     if (
                         abs(candidate[i] - candidate[j])
                         == abs(candidate[j] - candidate[k])
-                        and len(set([candidate[i], candidate[j], candidate[k]])) == 3
+                        and len({candidate[i], candidate[j], candidate[k]}) == 3
                     ):
                         passed.append(
                             sorted([candidate[i], candidate[j], candidate[k]])

@@ -45,7 +45,7 @@
 import os
 
 
-class PokerHand(object):
+class PokerHand:
     """Create an object representing a Poker Hand based on an input of a
     string which represents the best 5 card combination from the player's hand
     and board cards.
@@ -366,7 +366,7 @@ def solution() -> int:
     answer = 0
     script_dir = os.path.abspath(os.path.dirname(__file__))
     poker_hands = os.path.join(script_dir, "poker_hands.txt")
-    with open(poker_hands, "r") as file_hand:
+    with open(poker_hands) as file_hand:
         for line in file_hand:
             player_hand = line[:14].strip()
             opponent_hand = line[15:].strip()

@@ -217,7 +217,7 @@ def test_euler_project():
     answer = 0
     script_dir = os.path.abspath(os.path.dirname(__file__))
     poker_hands = os.path.join(script_dir, "poker_hands.txt")
-    with open(poker_hands, "r") as file_hand:
+    with open(poker_hands) as file_hand:
         for line in file_hand:
             player_hand = line[:14].strip()
             opponent_hand = line[15:].strip()

@@ -26,7 +26,7 @@ def solution(max_base: int = 10, max_power: int = 22) -> int:
     bases = range(1, max_base)
     powers = range(1, max_power)
     return sum(
-        1 for power in powers for base in bases if len(str((base ** power))) == power
+        1 for power in powers for base in bases if len(str(base ** power)) == power
     )
 
 

@@ -25,7 +25,7 @@ def solution():
     script_dir = os.path.dirname(os.path.realpath(__file__))
     triangle = os.path.join(script_dir, "triangle.txt")
 
-    with open(triangle, "r") as f:
+    with open(triangle) as f:
         triangle = f.readlines()
 
     a = map(lambda x: x.rstrip("\r\n").split(" "), triangle)