dtjoin_anti: Anti-join of 'DT' in a 'DT[i]'-style join of data frame-like...

In fjoin: Data Frame Joins Leveraging 'data.table'

Anti-join of DT in a DT[i]-style join of data frame-like objects

Description

Write (and optionally run) data.table code to return the anti-join of DT (the rows of DT not joining with i) using a generalisation of DT[i] syntax.

The functions fjoin_left_anti and fjoin_right_anti provide a more conventional interface that is recommended over dtjoin_anti for most users and cases.

Usage

dtjoin_anti(
  .DT = NULL,
  .i = NULL,
  on,
  match.na = FALSE,
  mult = "all",
  mult.DT = "all",
  nomatch = NULL,
  nomatch.DT = NULL,
  select = NULL,
  do = !(is.null(.DT) && is.null(.i)),
  show = !do,
  verbose = FALSE,
  ...
)

Arguments

.DT, .i	data.frame-like objects (plain, data.table, tibble, sf, list, etc.), or else both omitted for a mock join statement with no data.
on	A character vector of join predicates, e.g. c("id", "col_DT == col_i", "date < date", "cost <= budget"), or else NA for a natural join (an equality join on all same-named columns).
match.na	If TRUE, allow equality matches between NAs or NaNs. Default FALSE.
mult	(as in [.data.table) When a row of .i has multiple matching rows in .DT, which to accept. One of "all" (the default), "first", or "last".
mult.DT	Permitted for consistency with dtjoin but has no effect on the resulting semi-join.
nomatch, nomatch.DT	Permitted for consistency with dtjoin but have no effect on the resulting semi-join.
select	Character vector of columns of .DT to be selected. NULL (the default) selects all columns. Join columns are always selected.
do	Whether to execute the join. Default is TRUE unless .DT and .i are both omitted/NULL, in which case a mock join statement is produced.
show	Whether to print the code for the join to the console. Default is the opposite of do. If .DT and .i are both omitted/NULL, mock join code is displayed.
verbose	(passed to [.data.table) Whether data.table should print information to the console during execution. Default FALSE.
...	Further arguments (for internal use).

Details

Details are as for dtjoin except for arguments controlling the order and prefixing of output columns, which do not apply.

Value

A data.frame, data.table, (grouped) tibble, sf, or sf-tibble, or else NULL if do is FALSE. See Details.

See Also

See the package-level documentation fjoin for related functions.

Examples

# Mock joins

dtjoin_anti(on = "id")
dtjoin_anti(on = c("id", "date <= date"))
dtjoin_anti(on = c("id", "date <= date"), mult = "last")

fjoin documentation built on Dec. 11, 2025, 5:07 p.m.