all() and any() function

The all() function in Python is a built-in function that returns True if all elements in an iterable are True, and False otherwise. It takes an iterable (such as a list, tuple, or set) as its argument and returns a Boolean value.

row_len = len(matrix[0])
if not all(len(row) == row_len for row in matrix):
    raise TypeError('Each row of the matrix must have the same size')

In the context of the code provided, all(len(row) == row_len for row in matrix) checks if the length of each row in the matrix is equal to row_len. It iterates over each row in the matrix and evaluates whether the condition len(row) == row_len is True for all rows. If the condition is True for all rows, all() returns True. Otherwise, it returns False.

By using all() in this way, you can efficiently check if all rows in the matrix have the same length. If any row has a different length, the expression inside all() will evaluate to False, and a TypeError will be raised.

Here's an example to illustrate the usage of all():

# Check if all elements in the list are greater than 5
my_list = [6, 7, 8, 9]
result = all(elem > 5 for elem in my_list)
print(result)  # Output: True

# Check if all elements in the tuple are even
my_tuple = (2, 4, 6, 9)
result = all(elem % 2 == 0 for elem in my_tuple)
print(result)  # Output: False

In the first example, all elements in the list are greater than 5, so all() returns True. In the second example, there is one element in the tuple (9) that is not even, so all() returns False.

any()

The any() function is another built-in function in Python that returns True if at least one element in an iterable is True, and False if all elements are False. It takes an iterable as its argument and returns a Boolean value.

In the context of the code provided, you can use any() to check if there is at least one row in the matrix. This can be useful for verifying that the input matrix is not empty.

For example:

def matrix_divided(matrix, div):
    # Input validation checks
    if not isinstance(div, (int, float)):
        raise TypeError('div must be a number')
    if div == 0:
        raise ZeroDivisionError('division by zero')
    if not any(matrix):
        raise ValueError('matrix cannot be empty')
    if not all(isinstance(row, list) for row in matrix):
        raise TypeError('matrix must be a matrix (list of lists)')

    # Rest of the code...

In this example, the line if not any(matrix): checks if there is at least one row in the matrix. If any(matrix) returns False, it means the matrix is empty (all elements are False), and a ValueError is raised.

Here's another example to illustrate the usage of any():

# Check if any element in the list is negative
my_list = [1, 2, -3, 4]
result = any(elem < 0 for elem in my_list)
print(result)  # Output: True

# Check if any element in the tuple is a string
my_tuple = (10, 20, 30, 'hello')
result = any(isinstance(elem, str) for elem in my_tuple)
print(result)  # Output: True

In the first example, there is one element in the list (-3) that is negative, so any() returns True. In the second example, there is one element in the tuple ('hello') that is a string, so any() returns True.