Added pop() and __delitem__() methods.

README.md

@@ -68,7 +68,7 @@ the_device = MyDevice("255id:Dev:", name="my_device")
 assert registry.find("my_device") is the_device
 ```
 
-If this greedy behavior is suppressed with the *auto_register*
+This greedy behavior can be suppressed with the *auto_register*
 parameter. If *auto_register* is false, then a device class can be
 decorated to allow the registry to find it:
 
@@ -170,6 +170,36 @@ detector ("sim_det"), then access the *cam* attribute, and then cam's
 components.
 
 
+Removing Devices
+----------------
+
+The ``OphydRegistry`` class behaves similarly to a python dictionary.
+
+To **remove all devices** from the registry, use the ``clear()``
+method:
+
+```python
+
+registry.clear()
+```
+
+To **remove individual objects**, use either the *del* keyword, or the
+``pop()`` method. These approaches work with either the
+``OphydObject`` instance itself, or the instance's name:
+
+```python
+
+# Just delete the item and move on
+# (by name)
+del registry["motor1"]
+del registry[motor]
+
+# Remove the item and use it
+# (return ``None`` if motor1 is not in the registry)
+registry.pop("motor1", None)
+
+```
+
 Integrating with Typhos
 -----------------------
 

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "ophyd-registry"
-version = "0.8"
+version = "1.0.0"
 authors = [
   { name="Mark Wolfman", email="[email protected]" },
 ]
@@ -19,7 +19,7 @@ dependencies = ["ophyd"]
 
 [project.optional-dependencies]
 
-dev = ["black", "pytest", "build", "twine", "flake8", "caproto", "ruff"]
+dev = ["black", "isort", "pytest", "build", "twine", "flake8", "caproto", "ruff"]
 
 [project.urls]
 "Homepage" = "https://github.com/spc-group/ophyd-registry"
@@ -28,3 +28,6 @@ dev = ["black", "pytest", "build", "twine", "flake8", "caproto", "ruff"]
 [build-system]
 requires = ["setuptools>=61.0"]
 build-backend = "setuptools.build_meta"
+
+[tool.isort]
+profile = "black"

src/ophydregistry/__init__.py

@@ -1,2 +1,2 @@
-from .registry import Registry  # noqa: F401
 from .exceptions import ComponentNotFound, MultipleComponentsFound  # noqa: F401
+from .registry import Registry  # noqa: F401

src/ophydregistry/registry.py

@@ -1,11 +1,15 @@
-from typing import Optional, Mapping, List
 import logging
 import warnings
-from itertools import chain
 from collections import OrderedDict
+from itertools import chain
+from typing import List, Mapping, Optional
 
 from ophyd import ophydobj
 
+# Sentinal value for default parameters
+UNSET = object()
+
+
 try:
     import typhos
 except ImportError:
@@ -13,13 +17,12 @@
 else:
     typhos_available = True
 
 from .exceptions import (
-    MultipleComponentsFound,
     ComponentNotFound,
     InvalidComponentLabel,
+    MultipleComponentsFound,
 )
 
-
 log = logging.getLogger(__name__)
 
 
@@ -130,6 +133,40 @@
         """
         return self.find(key)
 
+    def __delitem__(self, key):
+        """Remove an object from the dicionary.
+
+        *key* can either be the device OphydObject or the name of an
+        OphydObject.
+
+        """
+        self.pop(key)
+
+    def pop(self, key, default=UNSET) -> ophydobj.OphydObject:
+        """Remove specified OphydObject and return it.
+
+        *key* can either be the device OphydObject or the name of an
+        OphydObject.
+
+        A default value can be provided that will be returned if the
+        object is not present.
+
+        """
+        # Locate the item
+        try:
+            obj = self[key]
+        except ComponentNotFound:
+            if default is not UNSET:
+                return default
+            else:
+                raise
+        # Remove from the list by name
+        del self._objects_by_name[obj.name]
+        # Remove from the list by label
+        for objects in self._objects_by_label.values():
+            objects.discard(obj)
+        return obj
+
     def clear(self, clear_typhos: bool = True):
         """Remove all previously registered components.
 

src/ophydregistry/tests/test_instrument_registry.py

@@ -1,9 +1,9 @@
 import logging
 
 import pytest
-from ophyd import sim, Device, EpicsMotor
+from ophyd import Device, EpicsMotor, sim
 
-from ophydregistry import Registry, ComponentNotFound, MultipleComponentsFound
+from ophydregistry import ComponentNotFound, MultipleComponentsFound, Registry
 
 
 @pytest.fixture()
@@ -372,7 +372,68 @@ def test_duplicate_device(caplog):
     assert "Ignoring readback with duplicate name" in caplog.text
     # Check that truly duplicated entries get a warning
     caplog.clear()
-    with (pytest.warns(UserWarning), caplog.at_level(logging.WARNING)):
-        registry.register(motor)
+    with caplog.at_level(logging.WARNING):
+        with pytest.warns(UserWarning):
+            registry.register(motor)
     # Check for the edge case where motor and motor.user_readback have the same name
     assert "Ignoring component with duplicate name" in caplog.text
+
+
+def test_delete_by_name():
+    """Check that we can remove an item from the ophyd registry."""
+    # Add an item to the registry
+    registry = Registry()
+    motor = sim.motor
+    registry.register(motor)
+    # Delete the item from the registry
+    del registry[motor.name]
+    # Check that the test fails
+    with pytest.raises(ComponentNotFound):
+        registry[motor.name]
+
+
+def test_pop_by_name():
+    """Check that we can remove an item from the ophyd registry."""
+    # Add an item to the registry
+    registry = Registry()
+    motor = sim.motor
+    registry.register(motor)
+    # Pop the item from the registry
+    popped = registry.pop(motor.name)
+    assert popped is motor
+    # Check that the test fails
+    with pytest.raises(ComponentNotFound):
+        registry[motor.name]
+    with pytest.raises(ComponentNotFound):
+        registry["motors"]
+
+
+def test_pop_by_object():
+    """Check that we can remove an item from the ophyd registry."""
+    # Add an item to the registry
+    registry = Registry()
+    motor = sim.motor
+    registry.register(motor)
+    # Pop the item from the registry
+    popped = registry.pop(motor)
+    assert popped is motor
+    # Check that the test fails
+    with pytest.raises(ComponentNotFound):
+        registry[motor.name]
+    with pytest.raises(ComponentNotFound):
+        registry["motors"]
+
+
+def test_pop_default():
+    """Check that we get a default object if our key is not present."""
+    # Add an item to the registry
+    registry = Registry()
+    motor = sim.motor
+    # Pop the item from the registry
+    popped = registry.pop("gibberish", motor)
+    assert popped is motor
+    # Check that the test fails
+    with pytest.raises(ComponentNotFound):
+        registry[motor.name]
+    with pytest.raises(ComponentNotFound):
+        registry["motors"]