Update matrix_operation.py

matrix/matrix_operation.py

@@ -1,39 +1,55 @@
 """
-function based version of matrix operations, which are just 2D arrays
+Functions for 2D matrix operations
 """
 
+from typing import List, Tuple
 
-def add(matrix_a, matrix_b):
+
+def add(matrix_a: List[list], matrix_b: List[list]) -> List[list]:
+    """
+    >>> add([[1,2],[3,4]],[[2,3],[4,5]])
+    [[3, 5], [7, 9]]
+    >>> add([[1.2,2.4],[3,4]],[[2,3],[4,5]])
+    [[3.2, 5.4], [7, 9]]
+    """
     if _check_not_integer(matrix_a) and _check_not_integer(matrix_b):
-        rows, cols = _verify_matrix_sizes(matrix_a, matrix_b)
-        matrix_c = []
-        for i in range(rows[0]):
-            list_1 = []
-            for j in range(cols[0]):
-                val = matrix_a[i][j] + matrix_b[i][j]
-                list_1.append(val)
-            matrix_c.append(list_1)
+        _verify_matrix_sizes(matrix_a, matrix_b)
+        matrix_c = [[i + j for i, j in zip(m, n)]
+                    for m, n in zip(matrix_a, matrix_b)]
         return matrix_c
 
 
-def subtract(matrix_a, matrix_b):
+def subtract(matrix_a: List[list], matrix_b: List[list]) -> List[list]:
+    """
+    >>> subtract([[1,2],[3,4]],[[2,3],[4,5]])
+    [[-1, -1], [-1, -1]]
+    >>> subtract([[1,2.5],[3,4]],[[2,3],[4,5.5]])
+    [[-1, -0.5], [-1, -1.5]]
+    """
     if _check_not_integer(matrix_a) and _check_not_integer(matrix_b):
-        rows, cols = _verify_matrix_sizes(matrix_a, matrix_b)
-        matrix_c = []
-        for i in range(rows[0]):
-            list_1 = []
-            for j in range(cols[0]):
-                val = matrix_a[i][j] - matrix_b[i][j]
-                list_1.append(val)
-            matrix_c.append(list_1)
+        _verify_matrix_sizes(matrix_a, matrix_b)
+        matrix_c = [[i - j for i, j in zip(m, n)]
+                    for m, n in zip(matrix_a, matrix_b)]
         return matrix_c
 
 
-def scalar_multiply(matrix, n):
+def scalar_multiply(matrix: List[list], n: int) -> List[list]:
+    """
+    >>> scalar_multiply([[1,2],[3,4]],5)
+    [[5, 10], [15, 20]]
+    >>> scalar_multiply([[1.4,2.3],[3,4]],5)
+    [[7.0, 11.5], [15, 20]]
+    """
     return [[x * n for x in row] for row in matrix]
 
 
-def multiply(matrix_a, matrix_b):
+def multiply(matrix_a: List[list], matrix_b: List[list]) -> List[list]:
+    """
+    >>> multiply([[1,2],[3,4]],[[5,5],[7,5]])
+    [[19, 15], [43, 35]]
+    >>> multiply([[1,2.5],[3,4.5]],[[5,5],[7,5]])
+    [[22.5, 17.5], [46.5, 37.5]]
+    """
     if _check_not_integer(matrix_a) and _check_not_integer(matrix_b):
         matrix_c = []
         rows, cols = _verify_matrix_sizes(matrix_a, matrix_b)
@@ -48,41 +64,55 @@ def multiply(matrix_a, matrix_b):
             for j in range(cols[1]):
                 val = 0
                 for k in range(cols[1]):
-                    val = val + matrix_a[i][k] * matrix_b[k][j]
+                    val += matrix_a[i][k] * matrix_b[k][j]
                 list_1.append(val)
             matrix_c.append(list_1)
         return matrix_c
 
 
-def identity(n):
+def identity(n: int) -> List[list]:
     """
     :param n: dimension for nxn matrix
     :type n: int
     :return: Identity matrix of shape [n, n]
+    >>> identity(3)
+    [[1, 0, 0], [0, 1, 0], [0, 0, 1]]
     """
     n = int(n)
     return [[int(row == column) for column in range(n)] for row in range(n)]
 
 
-def transpose(matrix, return_map=True):
+def transpose(matrix: List[list], return_map: bool = True) -> List[list]:
+    """
+    >>> transpose([[1,2],[3,4]]) # doctest: +ELLIPSIS
+    <map object at ...
+    >>> transpose([[1,2],[3,4]], return_map=False)
+    [[1, 3], [2, 4]]
+    """
     if _check_not_integer(matrix):
         if return_map:
             return map(list, zip(*matrix))
         else:
-            # mt = []
-            # for i in range(len(matrix[0])):
-            #     mt.append([row[i] for row in matrix])
-            # return mt
             return [[row[i] for row in matrix] for i in range(len(matrix[0]))]
 
 
-def minor(matrix, row, column):
-    minor = matrix[:row] + matrix[row + 1 :]
-    minor = [row[:column] + row[column + 1 :] for row in minor]
+def minor(matrix: List[list], row: int, column: int) -> List[list]:
+    """
+    >>> minor([[1, 2], [3, 4]], 1, 1)
+    [[1]]
+    """
+    minor = matrix[:row] + matrix[row + 1:]
+    minor = [row[:column] + row[column + 1:] for row in minor]
     return minor
 
 
-def determinant(matrix):
+def determinant(matrix: List[list]) -> int:
+    """
+    >>> determinant([[1, 2], [3, 4]])
+    -2
+    >>> determinant([[1.5, 2.5], [3, 4]])
+    -1.5
+    """
     if len(matrix) == 1:
         return matrix[0][0]
 
@@ -92,12 +122,18 @@ def determinant(matrix):
     return res
 
 
-def inverse(matrix):
+def inverse(matrix: List[list]) -> List[list]:
+    """
+    >>> inverse([[1, 2], [3, 4]])
+    [[-2.0, 1.0], [1.5, -0.5]]
+    >>> inverse([[1, 1], [1, 1]])
+    """
+    # https://stackoverflow.com/questions/20047519/python-doctests-test-for-none
     det = determinant(matrix)
     if det == 0:
         return None
 
-    matrix_minor = [[] for _ in range(len(matrix))]
+    matrix_minor = [[] for _ in matrix]
     for i in range(len(matrix)):
         for j in range(len(matrix)):
             matrix_minor[i].append(determinant(minor(matrix, i, j)))
@@ -110,17 +146,18 @@ def inverse(matrix):
     return scalar_multiply(adjugate, 1 / det)
 
 
-def _check_not_integer(matrix):
+def _check_not_integer(matrix: List[list]) -> bool:
     if not isinstance(matrix, int) and not isinstance(matrix[0], int):
         return True
     raise TypeError("Expected a matrix, got int/list instead")
 
 
-def _shape(matrix):
+def _shape(matrix: List[list]) -> list:
     return list((len(matrix), len(matrix[0])))
 
 
-def _verify_matrix_sizes(matrix_a, matrix_b):
+def _verify_matrix_sizes(
+        matrix_a: List[list], matrix_b: List[list]) -> Tuple[list]:
     shape = _shape(matrix_a)
     shape += _shape(matrix_b)
     if shape[0] != shape[2] or shape[1] != shape[3]:
@@ -134,21 +171,24 @@ def _verify_matrix_sizes(matrix_a, matrix_b):
 def main():
     matrix_a = [[12, 10], [3, 9]]
     matrix_b = [[3, 4], [7, 4]]
-    matrix_c = [[11, 12, 13, 14], [21, 22, 23, 24], [31, 32, 33, 34], [41, 42, 43, 44]]
+    matrix_c = [[11, 12, 13, 14], [21, 22, 23, 24],
+                [31, 32, 33, 34], [41, 42, 43, 44]]
     matrix_d = [[3, 0, 2], [2, 0, -2], [0, 1, 1]]
     print(
-        "Add Operation, %s + %s = %s \n"
-        % (matrix_a, matrix_b, (add(matrix_a, matrix_b)))
-    )
+        f"Add Operation, {matrix_a} + {matrix_b}"
+        f" = {add(matrix_a, matrix_b)} \n")
     print(
-        "Multiply Operation, %s * %s = %s \n"
-        % (matrix_a, matrix_b, multiply(matrix_a, matrix_b))
+        f"Multiply Operation, {matrix_a} * {matrix_b}",
+        f"= {multiply(matrix_a, matrix_b)} \n",
     )
-    print("Identity:  %s \n" % identity(5))
-    print("Minor of {} = {} \n".format(matrix_c, minor(matrix_c, 1, 2)))
-    print("Determinant of {} = {} \n".format(matrix_b, determinant(matrix_b)))
-    print("Inverse of {} = {}\n".format(matrix_d, inverse(matrix_d)))
+    print(f"Identity: {identity(5)}\n")
+    print(f"Minor of {matrix_c} = {minor(matrix_c, 1, 2)} \n")
+    print(f"Determinant of {matrix_b} = {determinant(matrix_b)} \n")
+    print(f"Inverse of {matrix_d} = {inverse(matrix_d)}\n")
 
 
 if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()
     main()

matrix/searching_in_sorted_matrix.py

@@ -1,14 +1,32 @@
-def search_in_a_sorted_matrix(mat, m, n, key):
+from typing import List
+
+
+def search_in_a_sorted_matrix(
+        mat: List[list], m: int, n: int, key: int or float) -> None:
+    '''
+    >>> search_in_a_sorted_matrix(\
+        [[2, 5, 7], [4, 8, 13], [9, 11, 15], [12, 17, 20]], 3, 3, 5)
+    Key 5 found at row- 1 column- 2
+    >>> search_in_a_sorted_matrix(\
+        [[2, 5, 7], [4, 8, 13], [9, 11, 15], [12, 17, 20]], 3, 3, 21)
+    Key 21 not found
+    >>> search_in_a_sorted_matrix(\
+        [[2.1, 5, 7], [4, 8, 13], [9, 11, 15], [12, 17, 20]], 3, 3, 2.1)
+    Key 2.1 found at row- 1 column- 1
+    >>> search_in_a_sorted_matrix(\
+        [[2.1, 5, 7], [4, 8, 13], [9, 11, 15], [12, 17, 20]], 3, 3, 2.2)
+    Key 2.2 not found
+    '''
     i, j = m - 1, 0
     while i >= 0 and j < n:
         if key == mat[i][j]:
-            print("Key {} found at row- {} column- {}".format(key, i + 1, j + 1))
+            print(f"Key {key} found at row- {i + 1} column- {j + 1}")
             return
         if key < mat[i][j]:
             i -= 1
         else:
             j += 1
-    print("Key %s not found" % (key))
+    print(f"Key {key} not found")
 
 
 def main():
@@ -19,4 +37,6 @@ def main():
 
 
 if __name__ == "__main__":
+    import doctest
+    doctest.testmod()
     main()