Copy matching colnames or indices to clipboard

[DesiQuintans]

One of the ways I've been using siftr lately is by incrementally building a query until I see all the columns I want. Once I have those, I want to be able to copy the column names or indices to my clipboard so that I can paste them into my script. I think it would be useful to have a workflow like:

sift(df, my, final, query)

# results...

pile_names(.Last.value)  # Should return .Last.value and copy colnames to clipboard as a side-effect

# Since .Last.value is returned, I can still grab the column numbers if I change my mind:
pile_nums(.Last.value)  # Should return .Last.value and copy column numbers to clipboard as a side-effect

The assumption of this workflow is that I keep submitting sift queries, and then if I like the results, I immediately copy them to the clipboard using .Last.value. I might have to append a class to the dictionary dataframe so that I can check if .Last.value is a sift() result.