How to use Application.UsedObjects in the xlwings API way

The Application.UsedObjects property in Excel’s object model provides a powerful way to access all objects that are currently in use within a workbook. In the context of xlwings, this property is exposed through the api property, allowing Python scripts to programmatically inspect and manage the resources consumed by an Excel instance. This is particularly useful for debugging memory issues, monitoring application performance, or programmatically cleaning up objects to prevent memory leaks in long-running automation tasks.

Functionality
The primary function of Application.UsedObjects is to return a Workbooks collection that represents all objects—such as ranges, charts, shapes, and named ranges—that are currently allocated in memory. This collection includes objects from all open workbooks. By accessing this property, developers can get a count of used objects or iterate through them to perform specific actions, like checking their properties or releasing them if necessary.

Syntax in xlwings
The xlwings library provides a Pythonic interface to Excel’s COM API. To access the UsedObjects property, you must first obtain the Excel Application object via xlwings. The typical syntax is:

import xlwings as xw

# Connect to the active Excel instance or start a new one
app = xw.apps.active.api # or xw.App().api for a new instance

# Access the UsedObjects property
used_objects = app.UsedObjects

Here, app is an xlwings proxy to the Excel Application object, and .api is used to access the underlying COM object. The UsedObjects property returns a collection that can be treated similarly to other Excel collections in xlwings.

Parameters and Usage
The UsedObjects property does not accept any parameters. It is a read-only property that provides a Workbooks collection. Key points to note:

• The collection’s Count property gives the total number of used objects.
• You can iterate through the collection using a for loop or access individual items by index (1-based indexing, as is standard in Excel VBA).
• Each item in the collection is an object that can be of various types (e.g., Range, Chart, Shape). You may need to inspect the object’s type to perform type-specific operations.

Example Code
Below is an xlwings API code example that demonstrates how to use the Application.UsedObjects property to list all used objects and their types in the active Excel instance:

import xlwings as xw

# Connect to the active Excel application
app = xw.apps.active.api

# Get the UsedObjects collection
used_objects = app.UsedObjects

# Print the count of used objects
print(f"Total used objects: {used_objects.Count}")

# Iterate through each used object and display its type and address (if applicable)
for i in range(1, used_objects.Count + 1):
    obj = used_objects.Item(i)
try:
    # Try to get the address for Range objects
    if hasattr(obj, 'Address'):
        print(f"Object {i}: Type={obj.__class__.__name__}, Address={obj.Address}")
    else:
        print(f"Object {i}: Type={obj.__class__.__name__}")
except Exception as e:
    print(f"Object {i}: Error accessing properties - {e}")

# Example: Release objects (if needed, by setting to None or closing workbooks)
# Note: Directly releasing objects from UsedObjects may require careful handling to avoid crashes.