Address from csv

R/pkg/R/functions.R

@@ -2223,12 +2223,19 @@ setMethod("from_json", signature(x = "Column", schema = "characterOrstructType")
 #' schema <- "city STRING, year INT"
 #' head(select(df, from_csv(df$csv, schema)))}
 #' @note from_csv since 3.0.0
-setMethod("from_csv", signature(x = "Column", schema = "character"),
+setMethod("from_csv", signature(x = "Column", schema = "characterOrColumn"),
           function(x, schema, ...) {
+            if (class(schema) == "Column") {
+              jschema <- schema@jc
+            } else if (is.character(schema)) {
+              jschema <- callJStatic("org.apache.spark.sql.functions", "lit", schema)
+            } else {
+              stop("schema argument should be a column or character")
+            }
             options <- varargsToStrEnv(...)
             jc <- callJStatic("org.apache.spark.sql.functions",
                               "from_csv",
-                              x@jc, schema, options)
+                              x@jc, jschema, options)
             column(jc)
           })
 

R/pkg/tests/fulltests/test_sparkSQL.R

@@ -1651,6 +1651,8 @@ test_that("column functions", {
   df <- as.DataFrame(list(list("col" = "1")))
   c <- collect(select(df, alias(from_csv(df$col, "a INT"), "csv")))
   expect_equal(c[[1]][[1]]$a, 1)
+  c <- collect(select(df, alias(from_csv(df$col, lit("a INT")), "csv")))
+  expect_equal(c[[1]][[1]]$a, 1)
 
   # Test to_json(), from_json()
   df <- sql("SELECT array(named_struct('name', 'Bob'), named_struct('name', 'Alice')) as people")

python/pyspark/sql/functions.py

@@ -25,9 +25,12 @@
 if sys.version < "3":
     from itertools import imap as map
 
+if sys.version >= '3':
+    basestring = str
+
 from pyspark import since, SparkContext
 from pyspark.rdd import ignore_unicode_prefix, PythonEvalType
-from pyspark.sql.column import Column, _to_java_column, _to_seq
+from pyspark.sql.column import Column, _to_java_column, _to_seq, _create_column_from_literal
 from pyspark.sql.dataframe import DataFrame
 from pyspark.sql.types import StringType, DataType
 # Keep UserDefinedFunction import for backwards compatible import; moved in SPARK-22409
@@ -2693,9 +2696,19 @@ def from_csv(col, schema, options={}):
     >>> df = spark.createDataFrame(data, ("key", "value"))
     >>> df.select(from_csv(df.value, "a INT").alias("csv")).collect()
     [Row(csv=Row(a=1))]
+    >>> df = spark.createDataFrame(data, ("key", "value"))
+    >>> df.select(from_csv(df.value, lit("a INT")).alias("csv")).collect()
+    [Row(csv=Row(a=1))]
     """
 
     sc = SparkContext._active_spark_context
+    if isinstance(schema, basestring):
+        schema = _create_column_from_literal(schema)
+    elif isinstance(schema, Column):
+        schema = _to_java_column(schema)
+    else:
+        raise TypeError("schema argument should be a column or string")
+
     jc = sc._jvm.functions.from_csv(_to_java_column(col), schema, options)
     return Column(jc)
 

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/csv/CSVUtils.scala → sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/csv/CSVExpressionUtils.scala

@@ -17,7 +17,7 @@
 
 package org.apache.spark.sql.catalyst.csv
 
-object CSVUtils {
+object CSVExpressionUtils {
   /**
    * Filter ignorable rows for CSV iterator (lines empty and starting with `comment`).
    * This is currently being used in CSV reading path and CSV schema inference.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/csv/CSVHeaderChecker.scala

@@ -123,7 +123,7 @@ class CSVHeaderChecker(
     // Note: if there are only comments in the first block, the header would probably
     // be not extracted.
     if (options.headerFlag && isStartOfFile) {
-      CSVUtils.extractHeader(lines, options).foreach { header =>
+      CSVExpressionUtils.extractHeader(lines, options).foreach { header =>
         checkHeaderColumnNames(tokenizer.parseLine(header))
       }
     }

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/csv/CSVOptions.scala

@@ -83,7 +83,7 @@ class CSVOptions(
     }
   }
 
-  val delimiter = CSVUtils.toChar(
+  val delimiter = CSVExpressionUtils.toChar(
     parameters.getOrElse("sep", parameters.getOrElse("delimiter", ",")))
   val parseMode: ParseMode =
     parameters.get("mode").map(ParseMode.fromString).getOrElse(PermissiveMode)

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/csv/UnivocityParser.scala

@@ -338,7 +338,7 @@ private[sql] object UnivocityParser {
 
     val options = parser.options
 
-    val filteredLines: Iterator[String] = CSVUtils.filterCommentAndEmpty(lines, options)
+    val filteredLines: Iterator[String] = CSVExpressionUtils.filterCommentAndEmpty(lines, options)
 
     val safeParser = new FailureSafeParser[String](
       input => Seq(parser.parse(input)),

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/csv/CSVUtilsSuite.scala

@@ -19,42 +19,42 @@ package org.apache.spark.sql.catalyst.csv
 
 import org.apache.spark.SparkFunSuite
 
-class CSVUtilsSuite extends SparkFunSuite {
+class CSVExpressionUtilsSuite extends SparkFunSuite {
   test("Can parse escaped characters") {
-    assert(CSVUtils.toChar("""\t""") === '\t')
-    assert(CSVUtils.toChar("""\r""") === '\r')
-    assert(CSVUtils.toChar("""\b""") === '\b')
-    assert(CSVUtils.toChar("""\f""") === '\f')
-    assert(CSVUtils.toChar("""\"""") === '\"')
-    assert(CSVUtils.toChar("""\'""") === '\'')
-    assert(CSVUtils.toChar("""\u0000""") === '\u0000')
-    assert(CSVUtils.toChar("""\\""") === '\\')
+    assert(CSVExpressionUtils.toChar("""\t""") === '\t')
+    assert(CSVExpressionUtils.toChar("""\r""") === '\r')
+    assert(CSVExpressionUtils.toChar("""\b""") === '\b')
+    assert(CSVExpressionUtils.toChar("""\f""") === '\f')
+    assert(CSVExpressionUtils.toChar("""\"""") === '\"')
+    assert(CSVExpressionUtils.toChar("""\'""") === '\'')
+    assert(CSVExpressionUtils.toChar("""\u0000""") === '\u0000')
+    assert(CSVExpressionUtils.toChar("""\\""") === '\\')
   }
 
   test("Does not accept delimiter larger than one character") {
     val exception = intercept[IllegalArgumentException]{
-      CSVUtils.toChar("ab")
+      CSVExpressionUtils.toChar("ab")
     }
     assert(exception.getMessage.contains("cannot be more than one character"))
   }
 
   test("Throws exception for unsupported escaped characters") {
     val exception = intercept[IllegalArgumentException]{
-      CSVUtils.toChar("""\1""")
+      CSVExpressionUtils.toChar("""\1""")
     }
     assert(exception.getMessage.contains("Unsupported special character for delimiter"))
   }
 
   test("string with one backward slash is prohibited") {
     val exception = intercept[IllegalArgumentException]{
-      CSVUtils.toChar("""\""")
+      CSVExpressionUtils.toChar("""\""")
     }
     assert(exception.getMessage.contains("Single backslash is prohibited"))
   }
 
   test("output proper error message for empty string") {
     val exception = intercept[IllegalArgumentException]{
-      CSVUtils.toChar("")
+      CSVExpressionUtils.toChar("")
     }
     assert(exception.getMessage.contains("Delimiter cannot be empty string"))
   }

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVDataSource.scala

@@ -35,7 +35,6 @@ import org.apache.spark.rdd.{BinaryFileRDD, RDD}
 import org.apache.spark.sql.{Dataset, Encoders, SparkSession}
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.csv.{CSVHeaderChecker, CSVOptions, UnivocityParser}
-import org.apache.spark.sql.catalyst.csv.CSVUtils.filterCommentAndEmpty
 import org.apache.spark.sql.execution.datasources._
 import org.apache.spark.sql.execution.datasources.text.TextFileFormat
 import org.apache.spark.sql.types.StructType
@@ -130,7 +129,7 @@ object TextInputCSVDataSource extends CSVDataSource {
         val header = CSVUtils.makeSafeHeader(firstRow, caseSensitive, parsedOptions)
         val sampled: Dataset[String] = CSVUtils.sample(csv, parsedOptions)
         val tokenRDD = sampled.rdd.mapPartitions { iter =>
-          val filteredLines = filterCommentAndEmpty(iter, parsedOptions)
+          val filteredLines = CSVUtils.filterCommentAndEmpty(iter, parsedOptions)
           val linesWithoutHeader =
             CSVUtils.filterHeaderLine(filteredLines, maybeFirstLine.get, parsedOptions)
           val parser = new CsvParser(parsedOptions.asParserSettings)

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVUtils.scala

@@ -19,6 +19,7 @@ package org.apache.spark.sql.execution.datasources.csv
 
 import org.apache.spark.rdd.RDD
 import org.apache.spark.sql.Dataset
+import org.apache.spark.sql.catalyst.csv.CSVExpressionUtils
 import org.apache.spark.sql.catalyst.csv.CSVOptions
 import org.apache.spark.sql.functions._
 
@@ -125,4 +126,7 @@ object CSVUtils {
       csv.sample(withReplacement = false, options.samplingRatio, 1)
     }
   }
+
+  def filterCommentAndEmpty(iter: Iterator[String], options: CSVOptions): Iterator[String] =
+    CSVExpressionUtils.filterCommentAndEmpty(iter, options)
 }

sql/core/src/main/scala/org/apache/spark/sql/functions.scala

@@ -3882,8 +3882,8 @@ object functions {
    * @group collection_funcs
    * @since 3.0.0
    */
-  def from_csv(e: Column, schema: String, options: java.util.Map[String, String]): Column = {
-    withExpr(new CsvToStructs(e.expr, lit(schema).expr, options.asScala.toMap))
+  def from_csv(e: Column, schema: Column, options: java.util.Map[String, String]): Column = {
+    withExpr(new CsvToStructs(e.expr, schema.expr, options.asScala.toMap))
   }
 
   // scalastyle:off line.size.limit

sql/core/src/test/scala/org/apache/spark/sql/CsvFunctionsSuite.scala

@@ -31,7 +31,7 @@ class CsvFunctionsSuite extends QueryTest with SharedSQLContext {
     val schema = "a int"
 
     checkAnswer(
-      df.select(from_csv($"value", schema, Map[String, String]().asJava)),
+      df.select(from_csv($"value", lit(schema), Map[String, String]().asJava)),
       Row(Row(1)) :: Nil)
   }