example-code-2e/11-pythonic-obj/vector2d_v0.py at master · fluentpython/example-code-2e · GitHub

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"""

A 2-dimensional vector class

# tag::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[]

"""

# tag::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[]

example-code-2e/11-pythonic-obj/vector2d_v0.py at master · fluentpython/example-code-2e · GitHub

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