last example of chapter 9: classes/vector_v5.py

classes/vector_v1.py

@@ -1,85 +1,124 @@
 """
-A 2-dimensional vector class
+A multi-dimensional ``Vector`` class, take 1
 
-    >>> v1 = Vector(3, 4)
-    >>> x, y = v1  #<1>
+A ``Vector`` is built from an iterable of numbers::
+
+    >>> Vector([3.1, 4.2])
+    Vector([3.1, 4.2])
+    >>> Vector((3, 4, 5))
+    Vector([3.0, 4.0, 5.0])
+    >>> Vector(range(10))
+    Vector([0.0, 1.0, 2.0, 3.0, 4.0, ...])
+
+
+Tests with 2-dimensions (same results as ``vector2d_v1.py``)::
+
+    >>> v1 = Vector([3, 4])
+    >>> x, y = v1
     >>> x, y
     (3.0, 4.0)
-    >>> v1  #<2>
-    Vector(3.0, 4.0)
-    >>> v1_clone = eval(repr(v1))  #<3>
+    >>> v1
+    Vector([3.0, 4.0])
+    >>> v1_clone = eval(repr(v1))
     >>> v1 == v1_clone
     True
-    >>> print(v1)  #<4>
+    >>> print(v1)
     (3.0, 4.0)
-    >>> octets = bytes(v1)  #<5>
+    >>> octets = bytes(v1)
     >>> octets
     b'\\x00\\x00\\x00\\x00\\x00\\x00\\x08@\\x00\\x00\\x00\\x00\\x00\\x00\\x10@'
-    >>> abs(v1)  #<6>
+    >>> abs(v1)
     5.0
-    >>> bool(v1), bool(Vector(0, 0))  #<7>
+    >>> bool(v1), bool(Vector([0, 0]))
     (True, False)
 
-Test of .frombytes() class method:
+
+Test of ``.frombytes()`` class method:
 
     >>> v1_clone = Vector.frombytes(bytes(v1))
     >>> v1_clone
-    Vector(3.0, 4.0)
+    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'
+Tests with 3-dimensions::
+
+    >>> v1 = Vector([3, 4, 5])
+    >>> x, y, z = v1
+    >>> x, y, z
+    (3.0, 4.0, 5.0)
+    >>> v1
+    Vector([3.0, 4.0, 5.0])
+    >>> v1_clone = eval(repr(v1))
+    >>> v1 == v1_clone
+    True
+    >>> print(v1)
+    (3.0, 4.0, 5.0)
+    >>> abs(v1)  # doctest:+ELLIPSIS
+    7.071067811...
+    >>> bool(v1), bool(Vector([0, 0, 0]))
+    (True, False)
+
+
+Tests with many dimensions::
+
+    >>> v7 = Vector(range(7))
+    >>> v7
+    Vector([0.0, 1.0, 2.0, 3.0, 4.0, ...])
+    >>> abs(v7)  # doctest:+ELLIPSIS
+    9.53939201...
+
+
+Test of ``.__bytes__`` and ``.frombytes()`` methods::
+
+    >>> v1 = Vector([3, 4, 5])
+    >>> v1_clone = Vector.frombytes(bytes(v1))
+    >>> v1_clone
+    Vector([3.0, 4.0, 5.0])
+    >>> v1 == v1_clone
+    True
 
-# END VECTOR_V1_UNHASHABLE_DEMO
 
 """
 
+# BEGIN VECTOR_V1
 from array import array
+import reprlib
 import math
 
 
 class Vector:
     typecode = 'd'
 
-    def __init__(self, x, y):
-        self.x = float(x)
-        self.y = float(y)
+    def __init__(self, components):
+        self._components = array(self.typecode, components)  # <1>
 
     def __iter__(self):
-        return (i for i in (self.x, self.y))
+        return iter(self._components)  # <2>
 
     def __repr__(self):
-        return 'Vector({!r}, {!r})'.format(*self)
+        components = reprlib.repr(self._components)  # <3>
+        components = components[components.find('['):-1] # <4>
+        return 'Vector({})'.format(components)
 
     def __str__(self):
         return str(tuple(self))
 
     def __bytes__(self):
-        return bytes(array(Vector.typecode, self))
+        return bytes(self._components)  # <5>
 
     def __eq__(self, other):
         return tuple(self) == tuple(other)
 
     def __abs__(self):
-        return math.hypot(self.x, self.y)
+        return math.sqrt(sum(x * x for x in self))  # <6>
 
     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>
+    @classmethod
+    def frombytes(cls, octets):
+        memv = memoryview(octets).cast(cls.typecode)
+        return cls(memv)  # <7>
 # END VECTOR_V1