FilesExpand file tree

 master

/

vector2d_v3_prophash.py

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

159 lines (122 loc) · 3.41 KB

 master

/

vector2d_v3_prophash.py

Copy path

Top

File metadata and controls

• Code
• Blame

159 lines (122 loc) · 3.41 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

"""

A 2-dimensional vector class

>>> v1 = Vector2d(3, 4)

>>> print(v1.x, v1.y)

3.0 4.0

>>> x, y = v1

>>> x, y

(3.0, 4.0)

>>> v1

Vector2d(3.0, 4.0)

>>> v1_clone = eval(repr(v1))

>>> v1 == v1_clone

True

>>> print(v1)

(3.0, 4.0)

>>> octets = bytes(v1)

>>> octets

b'd\\x00\\x00\\x00\\x00\\x00\\x00\\x08@\\x00\\x00\\x00\\x00\\x00\\x00\\x10@'

>>> abs(v1)

5.0

>>> bool(v1), bool(Vector2d(0, 0))

(True, False)

Test of ``.frombytes()`` class method:

>>> v1_clone = Vector2d.frombytes(bytes(v1))

>>> v1_clone

Vector2d(3.0, 4.0)

>>> v1 == v1_clone

True

Tests of ``format()`` with Cartesian coordinates:

>>> format(v1)

'(3.0, 4.0)'

>>> format(v1, '.2f')

'(3.00, 4.00)'

>>> format(v1, '.3e')

'(3.000e+00, 4.000e+00)'

Tests of the ``angle`` method::

>>> Vector2d(0, 0).angle()

0.0

>>> Vector2d(1, 0).angle()

0.0

>>> epsilon = 10**-8

>>> abs(Vector2d(0, 1).angle() - math.pi/2) < epsilon

True

>>> abs(Vector2d(1, 1).angle() - math.pi/4) < epsilon

True

Tests of ``format()`` with polar coordinates:

>>> format(Vector2d(1, 1), 'p') # doctest:+ELLIPSIS

'<1.414213..., 0.785398...>'

>>> format(Vector2d(1, 1), '.3ep')

'<1.414e+00, 7.854e-01>'

>>> format(Vector2d(1, 1), '0.5fp')

'<1.41421, 0.78540>'

# tag::VECTOR2D_V3_DEMO[]

Tests of `x` and `y` read-only properties:

>>> v1.x, v1.y

(3.0, 4.0)

>>> v1.x = 123

Traceback (most recent call last):

...

AttributeError: can't set attribute 'x'

# end::VECTOR2D_V3_HASH_DEMO[]

Tests of hashing:

# tag::VECTOR2D_V3_HASH_DEMO[]

>>> v1 = Vector2d(3, 4)

>>> v2 = Vector2d(3.1, 4.2)

>>> len({v1, v2})

2

# end::VECTOR2D_V3_DEMO[]

"""

from array import array

import math

# tag::VECTOR2D_V3_PROP[]

class Vector2d:

typecode = 'd'

def __init__(self, x, y):

self.__x = float(x) # <1>

self.__y = float(y)

@property # <2>

def x(self): # <3>

return self.__x # <4>

@property # <5>

def y(self):

return self.__y

def __iter__(self):

return (i for i in (self.x, self.y)) # <6>

# remaining methods: same as previous Vector2d

# end::VECTOR2D_V3_PROP[]

def __repr__(self):

class_name = type(self).__name__

return '{}({!r}, {!r})'.format(class_name, *self)

def __str__(self):

return str(tuple(self))

def __bytes__(self):

return (bytes([ord(self.typecode)]) +

bytes(array(self.typecode, self)))

def __eq__(self, other):

return tuple(self) == tuple(other)

# tag::VECTOR_V3_HASH[]

def __hash__(self):

return hash((self.x, self.y))

# end::VECTOR_V3_HASH[]

def __abs__(self):

return math.hypot(self.x, self.y)

def __bool__(self):

return bool(abs(self))

def angle(self):

return math.atan2(self.y, self.x)

def __format__(self, fmt_spec=''):

if fmt_spec.endswith('p'):

fmt_spec = fmt_spec[:-1]

coords = (abs(self), self.angle())

outer_fmt = '<{}, {}>'

else:

coords = self

outer_fmt = '({}, {})'

components = (format(c, fmt_spec) for c in coords)

return outer_fmt.format(*components)

@classmethod

def frombytes(cls, octets):

typecode = chr(octets[0])

memv = memoryview(octets[1:]).cast(typecode)

return cls(*memv)