Repository navigation
[R-Forge #2110] Add . and .. symbol prefixes and inherits=FALSE for strict scope #633
Description
Activity
- changed the title
[-][R-Forge #2110] Add .(), ..(), inherits=FALSE and maybe . and .. prefixes to symbols[/-][+][R-Forge #2110] Add . and .. symbol prefixes and inherits=FALSE for strict scope[/+]on Jun 17, 2014 would be useful here :
http://stackoverflow.com/questions/34077955/variable-usage-in-data-table- added a commit that references this issue
on Dec 8, 2016 Once version 10.2 is released (if not before), we should revisit this answer to remove the mention of
datatable.WhenJisSymbolThenCallingScope=TRUE. (As always, any of you should feel free to edit as you like).It'd be nice to be able to use this feature and the ! notation for excluding columns in tandem.
dt <- data.table(x = 1:10, y = rnorm(10), z = runif(10)) cols <- c('y', 'z') dt[, !..cols] # should return col x
I followed the SO issue here looking for this feature. Since, it is still experimental may I recommend that the syntax be changed from
..Ato..$Awhere..is a reference to the parent.frame. I believe this is more R-like, does the same thing and conforms to user expectations. It seems that this can be simply(?) done with:makeActiveBinding('..', parent.frame)Reacted by Mel B.Refer to #2186 for name mention under NEWS.
Another SO post: https://stackoverflow.com/q/45387223/
- removed this from the milestone
on May 10, 2018
Submitted by: Matt Dowle; Assigned to: Nobody; R-Forge link
inherits=FALSE would allow user to specify that j should use column names only, and if column name doesn't exist that should be error rather than possibly finding a match in calling scope.
..() is for the sub-join examples where the join goes in j and you want to refer to the columns in i not .SD. Something like that.