Make a shallow copy in data.table

Question

I read in the SO thread tester from Matt Dole about the function shallowto make small copies in data.table. However, I can no longer find the topic.

data.tabledoes not have an exported function named shallow. There is internal, but not documented. Can I use it safely? What is his behavior?

What I would like to do is an efficient copy of a large table. Let be DTa large table with columns nand a ffunction whose memory effectively adds a column. Maybe something like that.

DT2 = f(DT)

c DT2is data.tablewith columns npointing to the original addresses (without deep copies) and an additional one that exists only for DT2. If so, what adds to DT1if I doDT2[, col3 := NULL]

Answer 1

You cannot use it safely data.table:::shallow, no. It is not intentionally exported or intended for use by the user. Either from the point of view that he works, or his name or arguments will change in the future.

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