Making Custom Python Objects Hashable for Collections

class Coordinate:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __eq__(self, other):
        """
        Defines equality comparison for Coordinate objects.
        Required for hashable objects to ensure two equal objects have the same hash.
        """
        if not isinstance(other, Coordinate):
            return NotImplemented
        return self.x == other.x and self.y == other.y

    def __hash__(self):
        """
        Defines the hash value for Coordinate objects.
        Must be consistent with __eq__.
        """
        return hash((self.x, self.y)) # Hash of a tuple of immutable attributes

    def __repr__(self):
        return f"Coordinate({self.x}, {self.y})"

# Example Usage
coord1 = Coordinate(1, 2)
coord2 = Coordinate(1, 2)
coord3 = Coordinate(3, 4)

# Use as dictionary keys
coord_dict = {coord1: "Home", coord3: "Work"}
print(f"Value for coord1: {coord_dict[coord2]}") # Accessing with an equal object

# Use in a set
unique_coords = {coord1, coord2, coord3}
print(f"Unique coordinates in set: {unique_coords}") # Only 2 unique objects due to __eq__ and __hash__

# Demonstrating equality
print(f"coord1 == coord2: {coord1 == coord2}")
print(f"coord1 == coord3: {coord1 == coord3}")