ben-schwen commented on PR #45346: URL: https://github.com/apache/arrow/pull/45346#issuecomment-2613640506
> Yeah, this is even true if you don't attach `data.table` but interestingly even with the same `.internal.selfref` modifying `dt_in` does not result in changes in `dt_out` so they are seen as different objects with the same `.internal.selfref`. Nothing unexpected. It will even create the same `.internal.selfref` for different objects. ``` r library(data.table) dt = data.table(x=1:3) attributes(dt) #> $names #> [1] "x" #> #> $row.names #> [1] 1 2 3 #> #> $class #> [1] "data.table" "data.frame" #> #> $.internal.selfref #> <pointer: 0x5640ce7bc310> dt2 = data.table(x=1:3) attributes(dt2) #> $names #> [1] "x" #> #> $row.names #> [1] 1 2 3 #> #> $class #> [1] "data.table" "data.frame" #> #> $.internal.selfref #> <pointer: 0x5640ce7bc310> ``` But you can always check that they are not the same by checking `address(dt) != address(dt2)`. "Safe option" would be not to drop the `data.table` class but only drop the `.internal.selfref` attribute, so `data.table` will detect that and allocate the right memory. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
