Join methods should be for data.table not tbl_dt.

Closes #470
tidyverse · Aug 1, 2014 · b978eeb · b978eeb
1 parent cc0026a
commit b978eeb
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Showing 5 changed files with 26 additions and 16 deletions.
diff --git a/NAMESPACE b/NAMESPACE
@@ -3,8 +3,8 @@
 S3method(all.equal,tbl_df)
 S3method(all.equal,tbl_dt)
 S3method(anti_join,data.frame)
+S3method(anti_join,data.table)
 S3method(anti_join,tbl_df)
-S3method(anti_join,tbl_dt)
 S3method(anti_join,tbl_sql)
 S3method(arrange,data.frame)
 S3method(arrange,data.table)
@@ -122,14 +122,14 @@ S3method(groups,tbl_sql)
 S3method(head,tbl_dt)
 S3method(head,tbl_sql)
 S3method(inner_join,data.frame)
+S3method(inner_join,data.table)
 S3method(inner_join,tbl_df)
-S3method(inner_join,tbl_dt)
 S3method(inner_join,tbl_sql)
 S3method(intersect,data.frame)
 S3method(intersect,default)
 S3method(left_join,data.frame)
+S3method(left_join,data.table)
 S3method(left_join,tbl_df)
-S3method(left_join,tbl_dt)
 S3method(left_join,tbl_sql)
 S3method(mutate,data.frame)
 S3method(mutate,data.table)
@@ -200,8 +200,8 @@ S3method(select,tbl_df)
 S3method(select,tbl_dt)
 S3method(select,tbl_sql)
 S3method(semi_join,data.frame)
+S3method(semi_join,data.table)
 S3method(semi_join,tbl_df)
-S3method(semi_join,tbl_dt)
 S3method(semi_join,tbl_sql)
 S3method(setdiff,data.frame)
 S3method(setdiff,default)

diff --git a/NEWS.md b/NEWS.md
@@ -1,5 +1,8 @@
 # dplyr 0.2.0.99
 
+* joining two data.tables now correctly dispatches to data table methods,
+  and result is a data table (#470)
+
 * New `n_groups()` function tells you how many groups in a tbl. It returns
   1 for ungrouped data. (#477)
 

diff --git a/R/join-dt.r b/R/join-dt.r
@@ -58,15 +58,15 @@ join_dt <- function(op) {
 
 #' @export
 #' @rdname join.tbl_dt
-inner_join.tbl_dt <- join_dt(merge(x, y, by = by, allow.cartesian = TRUE))
+inner_join.data.table <- join_dt(merge(x, y, by = by, allow.cartesian = TRUE))
 
 #' @export
 #' @rdname join.tbl_dt
-left_join.tbl_dt  <- join_dt(merge(x, y, by = by, all.x = TRUE, allow.cartesian = TRUE))
+left_join.data.table  <- join_dt(merge(x, y, by = by, all.x = TRUE, allow.cartesian = TRUE))
 
 #' @export
 #' @rdname join.tbl_dt
-semi_join.tbl_dt  <- join_dt({
+semi_join.data.table  <- join_dt({
   # http://stackoverflow.com/questions/18969420/perform-a-semi-join-with-data-table
   w <- unique(x[y, which = TRUE, allow.cartesian = TRUE])
   w <- w[!is.na(w)]
@@ -75,4 +75,4 @@ semi_join.tbl_dt  <- join_dt({
 
 #' @export
 #' @rdname join.tbl_dt
-anti_join.tbl_dt <- join_dt(x[!y, allow.cartesian = TRUE])
+anti_join.data.table <- join_dt(x[!y, allow.cartesian = TRUE])
diff --git a/man/join.tbl_dt.Rd b/man/join.tbl_dt.Rd
@@ -1,19 +1,19 @@
 % Generated by roxygen2 (4.0.1): do not edit by hand
 \name{join.tbl_dt}
-\alias{anti_join.tbl_dt}
-\alias{inner_join.tbl_dt}
+\alias{anti_join.data.table}
+\alias{inner_join.data.table}
 \alias{join.tbl_dt}
-\alias{left_join.tbl_dt}
-\alias{semi_join.tbl_dt}
+\alias{left_join.data.table}
+\alias{semi_join.data.table}
 \title{Join data table tbls.}
 \usage{
-\method{inner_join}{tbl_dt}(x, y, by = NULL, copy = FALSE, ...)
+\method{inner_join}{data.table}(x, y, by = NULL, copy = FALSE, ...)
 
-\method{left_join}{tbl_dt}(x, y, by = NULL, copy = FALSE, ...)
+\method{left_join}{data.table}(x, y, by = NULL, copy = FALSE, ...)
 
-\method{semi_join}{tbl_dt}(x, y, by = NULL, copy = FALSE, ...)
+\method{semi_join}{data.table}(x, y, by = NULL, copy = FALSE, ...)
 
-\method{anti_join}{tbl_dt}(x, y, by = NULL, copy = FALSE, ...)
+\method{anti_join}{data.table}(x, y, by = NULL, copy = FALSE, ...)
 }
 \arguments{
 \item{x,y}{tbls to join}

diff --git a/tests/testthat/test-joins.r b/tests/testthat/test-joins.r
@@ -184,3 +184,10 @@ test_that("join functions error on column not found #371", {
     "No common variables"
   )
 })
+
+test_that("joining data tables yields a data table (#470)", {
+  out <- left_join(data.table(a), data.table(b))
+  expect_is(out, "data.table")
+  out <- semi_join(data.table(a), data.table(b))
+  expect_is(out, "data.table")
+})