[SPARK-10863][SPARKR] Method coltypes() (New version)

This is a follow up on PR #8984, as the corresponding branch for such PR was damaged.

Author: Oscar D. Lara Yejas <olarayej@mail.usf.edu>

Closes #9579 from olarayej/SPARK-10863_NEW14.

1 files changed, 49 insertions, 0 deletions

diff --git a/R/pkg/R/DataFrame.R b/R/pkg/R/DataFrame.R
index e9013aa34a..cc868069d1 100644
--- a/R/pkg/R/DataFrame.R
+++ b/R/pkg/R/DataFrame.R
@@ -2152,3 +2152,52 @@ setMethod("with",
             newEnv <- assignNewEnv(data)
             eval(substitute(expr), envir = newEnv, enclos = newEnv)
           })
+
+#' Returns the column types of a DataFrame.
+#' 
+#' @name coltypes
+#' @title Get column types of a DataFrame
+#' @family dataframe_funcs
+#' @param x (DataFrame)
+#' @return value (character) A character vector with the column types of the given DataFrame
+#' @rdname coltypes
+#' @examples \dontrun{
+#' irisDF <- createDataFrame(sqlContext, iris)
+#' coltypes(irisDF)
+#' }
+setMethod("coltypes",
+          signature(x = "DataFrame"),
+          function(x) {
+            # Get the data types of the DataFrame by invoking dtypes() function
+            types <- sapply(dtypes(x), function(x) {x[[2]]})
+
+            # Map Spark data types into R's data types using DATA_TYPES environment
+            rTypes <- sapply(types, USE.NAMES=F, FUN=function(x) {
+
+              # Check for primitive types
+              type <- PRIMITIVE_TYPES[[x]]
+
+              if (is.null(type)) {
+                # Check for complex types
+                for (t in names(COMPLEX_TYPES)) {
+                  if (substring(x, 1, nchar(t)) == t) {
+                    type <- COMPLEX_TYPES[[t]]
+                    break
+                  }
+                }
+
+                if (is.null(type)) {
+                  stop(paste("Unsupported data type: ", x))
+                }
+              }
+              type
+            })
+
+            # Find which types don't have mapping to R
+            naIndices <- which(is.na(rTypes))
+
+            # Assign the original scala data types to the unmatched ones
+            rTypes[naIndices] <- types[naIndices]
+
+            rTypes
+          })
\ No newline at end of file