Pyupgrade to python3.8 (TheAlgorithms#3616)

* Upgrade to Python 3.8 syntax

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: cclauss

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)

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:

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

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()
 

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()
 

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)

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()

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
             )
 

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
         """

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