fix(base): accept a list of rows in getmatrix and a range in getvector

getmatrix() raised TypeError for a nested list or tuple, such as a 2xN
path written as [[0, 1, 2], [0, 1, 0]], and getvector() raised TypeError
for a range. Convert a nested sequence to an array and check its shape
like any 2D array, and treat a range like a list.

A flat list is still reshaped as before.

Refs #255

Author: MrNK2107

spatialmath/base/argcheck.py

@@ -186,7 +186,8 @@ def getmatrix(
     :raises ValueError: if value is not of the specified shape
 
     ``getmatrix(m, shape)`` is a 2D matrix with shape ``shape`` formed from
-    ``m`` which can be a 2D array, 1D array-like or a scalar.
+    ``m`` which can be a 2D array, a list or tuple of rows, a 1D array-like
+    (including a ``range``) or a scalar.
 
     .. runblock:: pycon
 
@@ -197,6 +198,7 @@ def getmatrix(
         >>> getmatrix([3,4], (2, 1))
         >>> getmatrix([3,4,5,6], (2,2))
         >>> getmatrix(np.r_[3,4,5,6], (2,2))
+        >>> getmatrix([[0,1,2], [0,1,0]], (2,None))  # list of rows
 
     .. note::
 
@@ -213,6 +215,13 @@ def getmatrix(
     :seealso: :func:`ismatrix`, :func:`verifymatrix`
     :SymPy: supported
     """
+    if isinstance(m, range):
+        m = list(m)
+    if isinstance(m, (list, tuple)) and not isvector(m):
+        # passed a nested sequence, such as a list of rows: convert it and
+        # check its shape below
+        m = np.array(m)
+
     if isinstance(m, np.ndarray) and len(m.shape) == 2:
         # passed a 2D array
         mshape = m.shape
@@ -341,7 +350,7 @@ def getvector(
       where ``vec`` is any of:
 
         - a Python native int or float, a 1-vector
-        - Python native list or tuple
+        - Python native list, tuple or range
         - numPy real 1D array, ie. shape=(N,)
         - numPy real 2D array with a singleton dimension, ie. shape=(1,N)
           or (N,1)
@@ -386,6 +395,8 @@ def getvector(
     """
     dt = dtype
 
+    if isinstance(v, range):  # a range is a sequence of numbers
+        v = list(v)
     if isinstance(v, _scalartypes):  # handle scalar case
         v = [v]  # type: ignore
     if isinstance(v, (list, tuple)):

tests/base/test_argcheck.py

@@ -110,6 +110,31 @@ def test_getmatrix(self):
         with self.assertRaises(ValueError):
             m = getmatrix(a, (2, None))
 
+    def test_getmatrix_nested_sequence(self):
+        # a list of rows, as for a 2xN path of points (issue #255)
+        m = getmatrix([[0, 1, 2], [0, 1, 0]], (2, None))
+        self.assertIsInstance(m, np.ndarray)
+        nt.assert_array_equal(m, np.array([[0, 1, 2], [0, 1, 0]]))
+        self.assertEqual(m.dtype, np.float64)
+
+        # a list of tuples, Nx2
+        m = getmatrix([(0, 0), (1, 1), (2, 0)], (None, 2))
+        nt.assert_array_equal(m, np.array([[0, 0], [1, 1], [2, 0]]))
+
+        # a tuple of lists, fully specified shape
+        m = getmatrix(([1, 2], [3, 4]), (2, 2))
+        nt.assert_array_equal(m, np.array([[1, 2], [3, 4]]))
+
+        # the shape is checked, not reshaped
+        with self.assertRaises(ValueError):
+            getmatrix([[0, 1, 2], [0, 1, 0]], (3, None))
+        with self.assertRaises(ValueError):
+            getmatrix([[0, 0], [1, 1], [2, 0]], (2, None))
+
+        # a range is a 1D sequence of numbers
+        m = getmatrix(range(4), (2, 2))
+        nt.assert_array_equal(m, np.array([[0, 1], [2, 3]]))
+
     def test_verifymatrix(self):
         with self.assertRaises(TypeError):
             assertmatrix(3)
@@ -237,6 +262,20 @@ def test_homogeneous_conversion_unsupported_array_shapes(self):
                     with self.assertRaises(ValueError):
                         convert(np.ones(shape))
 
+    def test_getvector_range(self):
+        # a range is a sequence of numbers (issue #255)
+        v = getvector(range(1, 7))
+        self.assertIsInstance(v, np.ndarray)
+        nt.assert_array_equal(v, np.r_[1, 2, 3, 4, 5, 6])
+
+        v = getvector(range(3), 3, out="list")
+        self.assertEqual(v, [0, 1, 2])
+
+        v = getvector(range(3), out="col")
+        nt.assert_equal(v.shape, (3, 1))
+
+        nt.assert_raises(ValueError, getvector, range(3), 4)
+
     def test_getvector(self):
         l = [1, 2, 3]
         t = (1, 2, 3)