updated logic and added test

Author: venom1204

R/print.data.table.R

@@ -46,6 +46,7 @@ print.data.table = function(x, topn=getOption("datatable.print.topn"),
   topnmiss = missing(topn)
   topn = max(as.integer(topn),1L)
   show_trunc_message = isTRUE(trunc.cols)
+  n_col = ncol(x)
   if (print.keys) {
     if (!is.null(ky <- key(x)))
     catf("Key: <%s>\n", toString(ky))
@@ -89,7 +90,7 @@ print.data.table = function(x, topn=getOption("datatable.print.topn"),
     if (show.indices) toprint = cbind(toprint, index_dt)
   }
   if (show.ncols && !isTRUE(trunc.cols)) {
-    trunc_cols_message(character(0), NULL, FALSE, "none", ncol=ncol(toprint))
+    trunc_cols_message(character(0), NULL, FALSE, "none", ncol=n_col)
   }
   require_bit64_if_needed(x)
   classes = classes1(toprint)
@@ -127,7 +128,7 @@ print.data.table = function(x, topn=getOption("datatable.print.topn"),
     cols_to_print = widths < cons_width
     not_printed = colnames(toprint)[!cols_to_print]
     if (show.ncols) {
-      trunc_cols_message(not_printed, abbs, class, col.names, ncol=ncol(toprint))
+      trunc_cols_message(not_printed, abbs, class, col.names, ncol=n_col)
       show_trunc_message = FALSE
     }
 

inst/tests/tests.Rraw

@@ -21777,11 +21777,12 @@ test(2377.91, truelength(dt$a), 0L)
 test(2377.92, {setallocrow(dt); truelength(dt$a)}, 3L)
 
 #6663 Option to print the number of columns
-test(2378.1, capture.output(print(as.data.table(iris)))[1L], "Number of columns: 5", options=list(datatable.show.ncols=TRUE))
-test(2378.2, any(grepl("^Number of columns: 5$", capture.output(print(setkey(as.data.table(iris), Sepal.Length))))), TRUE, options=list(datatable.show.ncols=TRUE))
-test(2378.3, any(grepl("^[0-9]+ variables? not shown", capture.output(print(data.table(a=1:3, b=1:3, c=1:3, d=1:3, e=1:3), trunc.cols=TRUE)))), FALSE, options=list(width=20, datatable.show.ncols=TRUE))
-test(2378.4, capture.output(print(as.data.table(iris), trunc.cols=TRUE))[1L], "Number of columns: 5, of which 5 are not shown: [Sepal.Length, Sepal.Width, Petal.Length, Petal.Width, Species]", options=list(width=10, datatable.show.ncols=TRUE))
-test(2378.5, any(grepl("^Number of columns:", capture.output(print(as.data.table(iris))))), FALSE, options=list(datatable.show.ncols=FALSE))
-test(2378.6, capture.output(print(as.data.table(iris), trunc.cols=TRUE, class=TRUE))[1L], "Number of columns: 5, of which 5 are not shown: [Sepal.Length <num>, Sepal.Width <num>, Petal.Length <num>, Petal.Width <num>, Species <fctr>]", options=list(width=10, datatable.show.ncols=TRUE))
+test(2378.1, print(as.data.table(iris)), output="Number of columns: 5", options=list(datatable.show.ncols=TRUE))
+test(2378.2, print(setkey(as.data.table(iris), Sepal.Length)), output="Number of columns: 5", options=list(datatable.show.ncols=TRUE))
+test(2378.3, { dt = data.table(a=1:3, b=1:3, c=1:3, d=1:3, e=1:3); any(grepl("^[0-9]+ variables? not shown", capture.output(print(dt, trunc.cols=TRUE)))) }, FALSE, options=list(width=20, datatable.show.ncols=TRUE))
+test(2378.4, print(as.data.table(iris), trunc.cols=TRUE), output="Number of columns: 5, of which 5 are not shown: [Sepal.Length, Sepal.Width, Petal.Length, Petal.Width, Species]", options=list(width=10, datatable.show.ncols=TRUE))
+test(2378.5, any(grepl("Number of columns:", capture.output(print(as.data.table(iris))))), FALSE, options=list(datatable.show.ncols=FALSE))
+test(2378.6, print(as.data.table(iris), trunc.cols=TRUE, class=TRUE), output="Number of columns: 5, of which 5 are not shown: [Sepal.Length <num>, Sepal.Width <num>, Petal.Length <num>, Petal.Width <num>, Species <fctr>]", options=list(width=10, datatable.show.ncols=TRUE))
 test(2378.7, { dt = data.table(matrix(1:200, nrow=25)); out = capture.output(print(dt, trunc.cols=TRUE, class=TRUE)); grepl("<int>", out[length(out)]) }, TRUE, options=list(width=30, datatable.show.ncols=TRUE))
 test(2378.8, any(grepl("variable", capture.output(print(data.table(a=1), trunc.cols=TRUE)))), FALSE, options=list(width=80, datatable.show.ncols=FALSE))
+test(2378.9, print(setindex(data.table(a=1:2, b=3:4), a), show.ncols=TRUE, show.indices=TRUE), output="Number of columns: 2")