new dub()

@hadley: Do we want this in tibble (#31)?

NAMESPACE

@@ -35,6 +35,7 @@ export(as_data_frame)
 export(column_to_rownames)
 export(data_frame)
 export(data_frame_)
+export(dub)
 export(frame_data)
 export(glimpse)
 export(has_rownames)

R/dub.R

@@ -0,0 +1,19 @@
+#' Converting atomic vectors to data frames
+#'
+#' A helper function based on \code{\link{as_data_frame}} and
+#' \code{\link{rownames_to_column}}.
+#'
+#' @param x An atomic vector
+#' @param name,value Names of the columns that store the names and values
+#'
+#' @return
+#' @export
+#'
+#' @examples
+#' dub(1:3)
+#' dub(c(a = 5, b = 7))
+dub <- function(x, name = "name", value = "value") {
+  x <- rownames_to_column(as_data_frame(x))
+  names(x) <- c(name, value)
+  x
+}

tests/testthat/test-dub.R

@@ -0,0 +1,22 @@
+context("dub")
+
+test_that("can convert unnamed vector", {
+  expect_identical(dub(3:1),
+                   data_frame(name = as.character(1:3), value = 3:1))
+})
+
+test_that("can convert named vector", {
+  expect_identical(dub(c(a = 2, b = 1)),
+                   data_frame(name = letters[1:2], value = as.numeric(2:1)))
+})
+
+test_that("can convert zero-length vector", {
+  expect_identical(dub(logical()),
+                   data_frame(name = character(), value = logical()))
+})
+
+test_that("can use custom names", {
+  expect_identical(dub(letters, name = "index", value = "letter"),
+                   data_frame(index = as.character(seq_along(letters)),
+                              letter = letters))
+})