Merge pull request #1339 from MichaelChirico/setDTchk

Closes #1338: setDT gains check.names argument

R/data.table.R

@@ -2482,7 +2482,7 @@ setDF <- function(x, rownames=NULL) {
   invisible(x)
 }
 
-setDT <- function(x, keep.rownames=FALSE, key=NULL) {
+setDT <- function(x, keep.rownames=FALSE, key=NULL, check.names=FALSE) {
     name = substitute(x)
     if (is.name(name)) {
         home <- function(x, env) {
@@ -2501,10 +2501,12 @@ setDT <- function(x, keep.rownames=FALSE, key=NULL) {
         # fix for #1078 and #1128, see .resetclass() for explanation.
         setattr(x, 'class', .resetclass(x, 'data.table'))
         if (!missing(key)) setkeyv(x, key) # fix for #1169
+        if (check.names) setattr(x, "names", make.names(names(x), unique=TRUE))
         if (selfrefok(x) > 0) return(invisible(x)) else alloc.col(x)
     } else if (is.data.frame(x)) {
         rn = if (!identical(keep.rownames, FALSE)) rownames(x) else NULL
         setattr(x, "row.names", .set_row_names(nrow(x)))
+        if (check.names) setattr(x, "names", make.names(names(x), unique=TRUE))
         # fix for #1078 and #1128, see .resetclass() for explanation.
         setattr(x, "class", .resetclass(x, 'data.frame'))
         alloc.col(x)
@@ -2530,6 +2532,7 @@ setDT <- function(x, keep.rownames=FALSE, key=NULL) {
                 xn[idx] = paste("V", seq_along(which(idx)), sep="")
                 setattr(x, "names", xn)
             }
+            if (check.names) setattr(x, "names", make.names(xn, unique=TRUE))
         }
         setattr(x,"row.names",.set_row_names(max(n)))
         setattr(x,"class",c("data.table","data.frame"))

README.md

@@ -80,6 +80,8 @@
 
   24. `[.data.table` now accepts single column numeric matrix in `i` argument the same way as `data.frame`. Closes [#826](https://github.com/Rdatatable/data.table/issues/826). Thanks to @jangorecki for the PR.
 
+  25. `setDT()` gains `check.names` argument paralleling that of `fread`, `data.table`, and `base` functionality, allowing poorly declared objects to be converted to tidy `data.table`s by reference. Closes [#1338](https://github.com/Rdatatable/data.table/issues/1338); thanks to @MichaelChirico for the FR/PR.
+
 #### BUG FIXES
 
   1. `if (TRUE) DT[,LHS:=RHS]` no longer prints, [#869](https://github.com/Rdatatable/data.table/issues/869) and [#1122](https://github.com/Rdatatable/data.table/issues/1122). Tests added. To get this to work we've had to live with one downside: if a `:=` is used inside a function with no `DT[]` before the end of the function, then the next time `DT` or `print(DT)` is typed at the prompt, nothing will be printed. A repeated `DT` or `print(DT)` will print. To avoid this: include a `DT[]` after the last `:=` in your function. If that is not possible (e.g., it's not a function you can change) then `DT[]` at the prompt is guaranteed to print. As before, adding an extra `[]` on the end of a `:=` query is a recommended idiom to update and then print; e.g. `> DT[,foo:=3L][]`. Thanks to Jureiss and Jan Gorecki for reporting.

inst/tests/tests.Rraw

@@ -6956,6 +6956,15 @@ ans = data.table(AAA=as.integer(c(4,7,rep(1,17),31,21)),
                  CCC=as.integer(c(6,9,rep(3,17),33,23)))
 test(1558, fread(f, nrow=21L), ans) # no warning
 
+# FR # 1338 -- check.names argument of setDT
+ans=data.table(X=1:3,"X.1"=1:3)
+dt1<-data.table(X=1:3,X=1:3)
+df1<-data.frame(X=1:3,X=1:3,check.names=FALSE)
+ls1<-list("X"=1:3,"X"=1:3)
+test(1559.1, setDT(dt1, check.names=TRUE), ans)
+test(1559.1, setDT(df1, check.names=TRUE), ans)
+test(1559.1, setDT(ls1, check.names=TRUE), ans)
+
 ##########################