To return the names of all objects associated with R in a Databricks Notebook, you can use the ls() command in R to list all the objects in the current environment. Then, you can use the grep() function to search for objects containing the letter "R". Here's an example code:
```
# List all the objects in the current environment
objects <- ls()
# Search for objects containing the letter "R"
objectsR <- grep("R", objects, value = TRUE)
# Print the names of the objects containing "R"
print(objectsR)
``
This code will list all the objects in the current environment and then return the names of the objects that contain the letter "R". You can modify the grep()` function to search for other keywords or patterns if necessary.