Merge pull request #9 from robertzk/depth_0_lists

Depth 0 lists

DESCRIPTION

@@ -3,7 +3,7 @@ Type: Package
 Title: recombinator (http://github.com/robertzk/recombinator)
 Description: R tools for turning nested lists into data.frames
     in an orderly manner.
-Version: 0.1.2
+Version: 0.1.3
 Author: Robert Krzyzanowski <technoguyrob@gmail.com>
 Maintainer: Robert Krzyzanowski <technoguyrob@gmail.com>
 Authors@R: c(person("Robert", "Krzyzanowski",

NEWS.md

@@ -1,3 +1,7 @@
+# Version 0.1.3
+
+* Recombinator calls out to homogeneous recombinator correctly for depth-0 lists. Resolves #8.
+
 # Version 0.1.2
 
 * Recombinator calls out to homogeneous recombinator correctly when the names are a list within a list (instead of a vector). Resolves #6.

R/recombinator.R

@@ -27,19 +27,37 @@
 recombinator <- function(dat, id = "id") {
   if (!is.list(dat) || is.data.frame(dat)) {
   dat
-  } else if (is.list(dat[[1L]]) && (has_names(dat) || has_names(dat[[1L]]))) {
+  } else if (is_heterogeneous(dat)) {
     heterogeneous_recombinator(dat, id)
-  } else if (length(dat[[1L]]) > 1) {
+  } else if (is_homogeneous(dat)) {
     homogeneous_recombinator(dat, id)
   } else {
     stop("Invalid recombinator format: pass either (1) ",
-         "a list whose first element is a character vector of names",
+         "a list whose first element is a character vector of names ",
          "and the subsequent list elements are unnamed lists of values ",
          "or (2) a list each of whose elements are named lists.", call. = FALSE)
   }
 }
 
 
+#' Is this heterogeneous data?
+#' @param dat list. The list to verify.
+#' @return boolean. TRUE if the list is heterogeneous, FALSE otherwise.
+is_heterogeneous <- function(dat) {
+  is.list(dat[[1L]]) && (has_names(dat) || has_names(dat[[1L]]))
+}
+
+#' Is this homogeneous data?
+#' @param dat list. The list to verify.
+#' @return boolean. TRUE if the list is heterogeneous, FALSE otherwise.
+is_homogeneous <- function(dat) {
+  if (is_heterogeneous(dat)) { FALSE }
+  else if (is.character(dat[[1L]]) && !("list" %in% sapply(dat, class))) { TRUE }
+  else if (length(dat[[1L]]) > 1) { TRUE }
+  else { FALSE }
+}
+
+
 #' Checks if a list has names.
 #'
 #' @param dat list. The list to verify.

tests/testthat/test-recombinators.R

@@ -49,6 +49,17 @@ test_that("recombinator calls to homogeneous recombinator correctly #2.  Issue #
   expect_identical(recombinator(pre_dataframe), df)
 })
 
+test_that("recombinator calls to homogeneous recombinator for depth-0 lists. Issue #8", {
+  pre_dataframe <- list("title", 1, 2, 3)
+  df <- data.frame(title = c(1, 2, 3))
+  expect_identical(recombinator(pre_dataframe), df)
+})
+
+test_that("recombinator doesn't recombinate a depth-0 list with no first name.", {
+  pre_dataframe <- list(1, 2, 3)
+  expect_error(recombinator(pre_dataframe))
+})
+
 test_that("names that are different than make.names are nonstandard", {
   expect_warning(warn_on_nonstandard_names(list(`x:2` = 2)))
 })
@@ -64,5 +75,3 @@ test_that("a list with no names is not unstandard", {
 test_that("recombinator warns about nonstandard names", {
   expect_warning(homogeneous_recombinator(list(`x:2` = 2)))
 })
-
-