13.3 Mathematical Operators

Mathematical Operators

• __pow__ - implements the power operator for this class (**)

• __add__ - implements the addition operator for this class (+)

• __sub__ - implements the subtraction operator for this class (-)

• __mul__ - implements the multiplication operator for this class (*)

class Vector:

    def __init__(self, vals):
				"""
		    Constructor
		    self: a reference to the object we are creating
		    vals: a list of integers which are the contents of our vector
		    """
        self.vals = vals
        # print("Assigned values ", vals, " to vector.")

    def __str__(self):
				"""
		    String Function
		    Converts the object to a string in readable format for programmers
		    """
        return str(self.vals)

    def __pow__(self, power):
				"""
		    Elementwise power: raises each element in our vector to the given power
		    """
        return Vector([i ** power for i in self.vals])

    def __add__(self, vec):
				"""
		    Addition: adds each element to corresponding element in other vector
		    """
        return Vector(
            [self.vals[i] + vec.vals[i] for i in range(len(self.vals))]
        )

    def __mul__(self, constant):
				"""
		    Multiplies each element in the vector by a specified constant
		    """
        return Vector([self.vals[i] * constant for i in range(len(self.vals))])

    def __sub__(self, vec):
				"""
		    Elementwise subtraction: does same as addition, just subtraction instead
		    """
        return self + (vec * (-1))


vec = Vector([2, 3, 2])
otherVec = Vector([3, 4, 5])
print(str(vec))  # [2, 3, 2]
print(vec ** 2)  # [4, 9, 4]
print(vec - otherVec)  # [-1, -1, -3]
print(vec + otherVec)  # [5,  7, 7]
print(vec * 5)  # [10, 15, 10]

Practice

Matrix Add Subtract

Vector

Triangle