86 lines
1.8 KiB
Python
86 lines
1.8 KiB
Python
"""
|
|
A 2-dimensional vector class
|
|
|
|
>>> v1 = Vector(3, 4)
|
|
>>> x, y = v1 #<1>
|
|
>>> x, y
|
|
(3.0, 4.0)
|
|
>>> v1 #<2>
|
|
Vector(3.0, 4.0)
|
|
>>> v1_clone = eval(repr(v1)) #<3>
|
|
>>> v1 == v1_clone
|
|
True
|
|
>>> print(v1) #<4>
|
|
(3.0, 4.0)
|
|
>>> octets = bytes(v1) #<5>
|
|
>>> octets
|
|
b'\\x00\\x00\\x00\\x00\\x00\\x00\\x08@\\x00\\x00\\x00\\x00\\x00\\x00\\x10@'
|
|
>>> abs(v1) #<6>
|
|
5.0
|
|
>>> bool(v1), bool(Vector(0, 0)) #<7>
|
|
(True, False)
|
|
|
|
Test of .frombytes() class method:
|
|
|
|
>>> v1_clone = Vector.frombytes(bytes(v1))
|
|
>>> v1_clone
|
|
Vector(3.0, 4.0)
|
|
>>> v1 == v1_clone
|
|
True
|
|
|
|
So far, Vector instances are unhashable:
|
|
|
|
# BEGIN VECTOR_V1_UNHASHABLE_DEMO
|
|
>>> v1 = Vector(3, 4)
|
|
>>> hash(v1)
|
|
Traceback (most recent call last):
|
|
...
|
|
TypeError: unhashable type: 'Vector'
|
|
>>> set([v1])
|
|
Traceback (most recent call last):
|
|
...
|
|
TypeError: unhashable type: 'Vector'
|
|
|
|
# END VECTOR_V1_UNHASHABLE_DEMO
|
|
|
|
"""
|
|
|
|
from array import array
|
|
import math
|
|
|
|
|
|
class Vector:
|
|
typecode = 'd'
|
|
|
|
def __init__(self, x, y):
|
|
self.x = float(x)
|
|
self.y = float(y)
|
|
|
|
def __iter__(self):
|
|
return (i for i in (self.x, self.y))
|
|
|
|
def __repr__(self):
|
|
return 'Vector({!r}, {!r})'.format(*self)
|
|
|
|
def __str__(self):
|
|
return str(tuple(self))
|
|
|
|
def __bytes__(self):
|
|
return bytes(array(Vector.typecode, self))
|
|
|
|
def __eq__(self, other):
|
|
return tuple(self) == tuple(other)
|
|
|
|
def __abs__(self):
|
|
return math.hypot(self.x, self.y)
|
|
|
|
def __bool__(self):
|
|
return bool(abs(self))
|
|
|
|
# BEGIN VECTOR_V1
|
|
@classmethod # <1>
|
|
def frombytes(cls, octets): # <2>
|
|
memv = memoryview(octets).cast(cls.typecode) # <3>
|
|
return cls(*memv) # <4>
|
|
# END VECTOR_V1
|