[SPARK-23920][SQL]add array_remove to remove all elements that equal element from array

python/pyspark/sql/functions.py

@@ -1964,6 +1964,22 @@ def element_at(col, extraction):
     return Column(sc._jvm.functions.element_at(_to_java_column(col), extraction))
 
 
+@since(2.4)
+def array_remove(col, element):
+    """
+    Collection function: Remove all elements that equal to element from the given array.
+
+    :param col: name of column containing array
+    :param element: element to be removed from the array
+
+    >>> df = spark.createDataFrame([([1, 2, 3, 1, 1],), ([],)], ['data'])
+    >>> df.select(array_remove(df.data, 1)).collect()
+    [Row(array_remove(data, 1)=[2, 3]), Row(array_remove(data, 1)=[])]
+    """
+    sc = SparkContext._active_spark_context
+    return Column(sc._jvm.functions.array_remove(_to_java_column(col), element))
+
+
 @since(1.4)
 def explode(col):
     """Returns a new row for each element in the given array or map.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala

@@ -429,6 +429,7 @@ object FunctionRegistry {
     expression[Concat]("concat"),
     expression[Flatten]("flatten"),
     expression[ArrayRepeat]("array_repeat"),
+    expression[ArrayRemove]("array_remove"),
     CreateStruct.registryEntry,
 
     // misc functions

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/collectionOperations.scala

@@ -1882,3 +1882,98 @@ case class ArrayRepeat(left: Expression, right: Expression)
   }
 
 }
+
+/**
+ * Remove all elements that equal to element from the given array
+ */
+@ExpressionDescription(
+  usage = "_FUNC_(array, element) - Remove all elements that equal to element from array.",
+  examples = """
+    Examples:
+      > SELECT _FUNC_(array(1, 2, 3, null, 3), 3);
+       [1,2,null]
+  """, since = "2.4.0")
+case class ArrayRemove(left: Expression, right: Expression)
+  extends BinaryExpression with ImplicitCastInputTypes {
+
+  override def dataType: DataType = left.dataType
+
+  override def inputTypes: Seq[AbstractDataType] =
+    Seq(ArrayType, left.dataType.asInstanceOf[ArrayType].elementType)
+
+  lazy val elementType: DataType = left.dataType.asInstanceOf[ArrayType].elementType
+
+  override def nullSafeEval(arr: Any, value: Any): Any = {
+    val elementType = left.dataType.asInstanceOf[ArrayType].elementType
+    val data = arr.asInstanceOf[ArrayData].toArray[AnyRef](elementType).filter(_ != value)
+    new GenericArrayData(data.asInstanceOf[Array[Any]])
+  }
+
+  override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+    nullSafeCodeGen(ctx, ev, (arr, value) => {
+      val numsToRemove = ctx.freshName("numsToRemove")
+      val newArraySize = ctx.freshName("newArraySize")
+      val i = ctx.freshName("i")
+      val getValue = CodeGenerator.getValue(arr, elementType, i)
+      val isEqual = ctx.genEqual(elementType, value, getValue)
+      s"""
+         |int $numsToRemove = 0;
+         |for (int $i = 0; $i < $arr.numElements(); $i ++) {
+         |  if (!$arr.isNullAt($i) && $isEqual) {
+         |    $numsToRemove = $numsToRemove + 1;
+         |  }
+         |}
+         |int $newArraySize = $arr.numElements() - $numsToRemove;
+         |${genCodeForResult(ctx, ev, arr, value, newArraySize)}
+       """.stripMargin
+    })
+  }
+
+  def genCodeForResult(
+      ctx: CodegenContext,
+      ev: ExprCode,
+      inputArray: String,
+      value: String,
+      newArraySize: String): String = {
+    val values = ctx.freshName("values")
+    val i = ctx.freshName("i")
+    val pos = ctx.freshName("pos")
+    val getValue = CodeGenerator.getValue(inputArray, elementType, i)
+    val isEqual = ctx.genEqual(elementType, value, getValue)
+    if (!CodeGenerator.isPrimitiveType(elementType)) {
+      val arrayClass = classOf[GenericArrayData].getName
+      s"""
+         |int $pos = 0;
+         |Object[] $values = new Object[$newArraySize];
+         |for (int $i = 0; $i < $inputArray.numElements(); $i ++) {
+         |  if (!($isEqual)) {
+         |    $values[$pos] = $getValue;
+         |    $pos = $pos + 1;
+         |  }
+         |}
+         |${ev.value} = new $arrayClass($values);
+       """.stripMargin
+    } else {
+      val primitiveValueTypeName = CodeGenerator.primitiveTypeName(elementType)
+      s"""
+         |${ctx.createUnsafeArray(values, newArraySize, elementType, s" $prettyName failed.")}
+         |int $pos = 0;
+         |for (int $i = 0; $i < $inputArray.numElements(); $i ++) {
+         |  if ($inputArray.isNullAt($i)) {
+         |      $values.setNullAt($pos);
+         |      $pos = $pos + 1;
+         |  }
+         |  else {
+         |    if (!($isEqual)) {
+         |      $values.set$primitiveValueTypeName($pos, $getValue);
+         |      $pos = $pos + 1;
+         |    }
+         |  }
+         |}
+         |${ev.value} = $values;
+       """.stripMargin
+    }
+  }
+
+  override def prettyName: String = "array_remove"
+}

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/CollectionExpressionsSuite.scala

@@ -552,4 +552,36 @@ class CollectionExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper
     checkEvaluation(ArrayRepeat(strArray, Literal(2)), Seq(Seq("hi", "hola"), Seq("hi", "hola")))
     checkEvaluation(ArrayRepeat(Literal("hi"), Literal(null, IntegerType)), null)
   }
+
+  test("Array remove") {
+    val a0 = Literal.create(Seq(1, 2, 3, 2, 2, 5), ArrayType(IntegerType))
+    val a1 = Literal.create(Seq("b", "a", "a", "c", "b"), ArrayType(StringType))
+    val a2 = Literal.create(Seq[String](null, "", null, ""), ArrayType(StringType))
+    val a3 = Literal.create(Seq.empty[Integer], ArrayType(IntegerType))
+    val a4 = Literal.create(null, ArrayType(StringType))
+    val a5 = Literal.create(Seq(1, null, 8, 9, null), ArrayType(IntegerType))
+    val a6 = Literal.create(Seq(true, false, false, true), ArrayType(BooleanType))
+
+    checkEvaluation(ArrayRemove(a0, Literal(0)), Seq(1, 2, 3, 2, 2, 5))
+    checkEvaluation(ArrayRemove(a0, Literal(1)), Seq(2, 3, 2, 2, 5))
+    checkEvaluation(ArrayRemove(a0, Literal(2)), Seq(1, 3, 5))
+    checkEvaluation(ArrayRemove(a0, Literal(3)), Seq(1, 2, 2, 2, 5))
+    checkEvaluation(ArrayRemove(a0, Literal(5)), Seq(1, 2, 3, 2, 2))
+    checkEvaluation(ArrayRemove(a0, Literal(null, IntegerType)), null)
+
+    checkEvaluation(ArrayRemove(a1, Literal("")), Seq("b", "a", "a", "c", "b"))
+    checkEvaluation(ArrayRemove(a1, Literal("a")), Seq("b", "c", "b"))
+    checkEvaluation(ArrayRemove(a1, Literal("b")), Seq("a", "a", "c"))
+    checkEvaluation(ArrayRemove(a1, Literal("c")), Seq("b", "a", "a", "b"))
+
+    checkEvaluation(ArrayRemove(a2, Literal("")), Seq(null, null))
+    checkEvaluation(ArrayRemove(a2, Literal(null, StringType)), null)
+
+    checkEvaluation(ArrayRemove(a3, Literal(1)), Seq.empty[Integer])
+
+    checkEvaluation(ArrayRemove(a4, Literal("a")), null)
+
+    checkEvaluation(ArrayRemove(a5, Literal(9)), Seq(1, null, 8, null))
+    checkEvaluation(ArrayRemove(a6, Literal(false)), Seq(true, true))
+  }
 }

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

@@ -3169,6 +3169,15 @@ object functions {
    */
   def array_sort(e: Column): Column = withExpr { ArraySort(e.expr) }
 
+  /**
+   * Remove all elements that equal to element from the given array.
+   * @group collection_funcs
+   * @since 2.4.0
+   */
+  def array_remove(column: Column, element: Any): Column = withExpr {
+    ArrayRemove(column.expr, Literal(element))
+  }
+
   /**
    * Creates a new row for each element in the given array or map column.
    *

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

@@ -948,6 +948,30 @@ class DataFrameFunctionsSuite extends QueryTest with SharedSQLContext {
 
   }
 
+  test("array remove") {
+    val df = Seq(
+      (Array[Int](2, 1, 2, 3), Array("a", "b", "c", "a"), Array("", "")),
+      (Array.empty[Int], Array.empty[String], Array.empty[String]),
+      (null, null, null)
+    ).toDF("a", "b", "c")
+    checkAnswer(
+      df.select(array_remove($"a", 2), array_remove($"b", "a"), array_remove($"c", "")),
+      Seq(
+        Row(Seq(1, 3), Seq("b", "c"), Seq.empty[String]),
+        Row(Seq.empty[Int], Seq.empty[String], Seq.empty[String]),
+        Row(null, null, null))
+    )
+
+    checkAnswer(
+      df.selectExpr("array_remove(a, 2)", "array_remove(b, \"a\")",
+        "array_remove(c, \"\")"),
+      Seq(
+        Row(Seq(1, 3), Seq("b", "c"), Seq.empty[String]),
+        Row(Seq.empty[Int], Seq.empty[String], Seq.empty[String]),
+        Row(null, null, null))
+    )
+  }
+
   private def assertValuesDoNotChangeAfterCoalesceOrUnion(v: Column): Unit = {
     import DataFrameFunctionsSuite.CodegenFallbackExpr
     for ((codegenFallback, wholeStage) <- Seq((true, false), (false, false), (false, true))) {