example-code-2e/11-pythonic-obj/vector2d_v0.py
2019-04-06 07:11:08 -03:00

65 lines
1.4 KiB
Python

"""
A 2-dimensional vector class
# BEGIN VECTOR2D_V0_DEMO
>>> v1 = Vector2d(3, 4)
>>> print(v1.x, v1.y) # <1>
3.0 4.0
>>> x, y = v1 # <2>
>>> x, y
(3.0, 4.0)
>>> v1 # <3>
Vector2d(3.0, 4.0)
>>> v1_clone = eval(repr(v1)) # <4>
>>> v1 == v1_clone # <5>
True
>>> print(v1) # <6>
(3.0, 4.0)
>>> octets = bytes(v1) # <7>
>>> octets
b'd\\x00\\x00\\x00\\x00\\x00\\x00\\x08@\\x00\\x00\\x00\\x00\\x00\\x00\\x10@'
>>> abs(v1) # <8>
5.0
>>> bool(v1), bool(Vector2d(0, 0)) # <9>
(True, False)
# END VECTOR2D_V0_DEMO
"""
# BEGIN VECTOR2D_V0
from array import array
import math
class Vector2d:
typecode = 'd' # <1>
def __init__(self, x, y):
self.x = float(x) # <2>
self.y = float(y)
def __iter__(self):
return (i for i in (self.x, self.y)) # <3>
def __repr__(self):
class_name = type(self).__name__
return '{}({!r}, {!r})'.format(class_name, *self) # <4>
def __str__(self):
return str(tuple(self)) # <5>
def __bytes__(self):
return (bytes([ord(self.typecode)]) + # <6>
bytes(array(self.typecode, self))) # <7>
def __eq__(self, other):
return tuple(self) == tuple(other) # <8>
def __abs__(self):
return math.hypot(self.x, self.y) # <9>
def __bool__(self):
return bool(abs(self)) # <10>
# END VECTOR2D_V0