Class _ElementListView

dm_control/mjcf/element.py:1326–1419

A hybrid list/dict-like view to a group of repeated MJCF elements.

class _ElementListView:
  """A hybrid list/dict-like view to a group of repeated MJCF elements."""

  def __init__(self, spec, parent):
    self._spec = spec
    self._parent = parent
    self._elements = self._parent._children  # pylint: disable=protected-access
    self._scoped_elements = collections.OrderedDict(
        [(scope_namescope.name, getattr(scoped_parent, self._spec.name))
         for scope_namescope, scoped_parent
         in self._parent._attachments.items()])

  @property
  def spec(self):
    return self._spec

  @property
  def tag(self):
    return self._spec.name

  @property
  def namescope(self):
    return self._parent.namescope

  @property
  def parent(self):
    return self._parent

  def __len__(self):
    return len(self._full_list())

  def __iter__(self):
    return iter(self._full_list())

  def _identifier_not_found_error(self, index):
    return KeyError('An element <{}> with {}={!r} does not exist'
                    .format(self._spec.name, self._spec.identifier, index))

  def _find_index(self, index):
    """Locates an element given the index among siblings with the same tag."""
    if isinstance(index, str) and self._spec.identifier:
      for i, element in enumerate(self._elements):
        if (element.tag == self._spec.name
            and getattr(element, self._spec.identifier) == index):
          return i
      raise self._identifier_not_found_error(index)
    else:
      count = 0
      for i, element in enumerate(self._elements):
        if element.tag == self._spec.name:
          if index == count:
            return i
          else:
            count += 1
      raise IndexError('list index out of range')

  def _full_list(self):
    out_list = [element for element in self._elements