From 9fe3adccef687c92ff1ac17d946af089c8e28d66 Mon Sep 17 00:00:00 2001
From: Cheng Hao <hao.cheng@intel.com>
Date: Wed, 10 Jun 2015 19:55:10 -0700
Subject: [PATCH] [SPARK-8248][SQL] string function: length
Author: Cheng Hao <hao.cheng@intel.com>
Closes #6724 from chenghao-intel/length and squashes the following commits:
aaa3c31 [Cheng Hao] revert the additional change
97148a9 [Cheng Hao] remove the codegen testing temporally
ae08003 [Cheng Hao] update the comments
1eb1fd1 [Cheng Hao] simplify the code as commented
3e92d32 [Cheng Hao] use the selectExpr in unit test intead of SQLQuery
3c729aa [Cheng Hao] fix bug for constant null value in codegen
3641f06 [Cheng Hao] keep the length() method for registered function
8e30171 [Cheng Hao] update the code as comment
db604ae [Cheng Hao] Add code gen support
548d2ef [Cheng Hao] register the length()
09a0738 [Cheng Hao] add length support
---
.../catalyst/analysis/FunctionRegistry.scala | 13 +++++++-----
.../sql/catalyst/expressions/Expression.scala | 3 +++
.../expressions/stringOperations.scala | 21 +++++++++++++++++++
.../expressions/StringFunctionsSuite.scala | 12 +++++++++++
.../org/apache/spark/sql/functions.scala | 18 ++++++++++++++++
.../spark/sql/DataFrameFunctionsSuite.scala | 20 ++++++++++++++++++
6 files changed, 82 insertions(+), 5 deletions(-)
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala
index ba89a5c8d1..39875d7f21 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala
@@ -89,14 +89,10 @@ object FunctionRegistry {
expression[CreateArray]("array"),
expression[Coalesce]("coalesce"),
expression[Explode]("explode"),
- expression[Lower]("lower"),
- expression[Substring]("substr"),
- expression[Substring]("substring"),
expression[Rand]("rand"),
expression[Randn]("randn"),
expression[CreateStruct]("struct"),
expression[Sqrt]("sqrt"),
- expression[Upper]("upper"),
// Math functions
expression[Acos]("acos"),
@@ -132,7 +128,14 @@ object FunctionRegistry {
expression[Last]("last"),
expression[Max]("max"),
expression[Min]("min"),
- expression[Sum]("sum")
+ expression[Sum]("sum"),
+
+ // string functions
+ expression[Lower]("lower"),
+ expression[StringLength]("length"),
+ expression[Substring]("substr"),
+ expression[Substring]("substring"),
+ expression[Upper]("upper")
)
val builtin: FunctionRegistry = {
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Expression.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Expression.scala
index 63dd5f9854..8c1e4d74f9 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Expression.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Expression.scala
@@ -212,6 +212,9 @@ abstract class LeafExpression extends Expression with trees.LeafNode[Expression]
abstract class UnaryExpression extends Expression with trees.UnaryNode[Expression] {
self: Product =>
+ override def foldable: Boolean = child.foldable
+ override def nullable: Boolean = child.nullable
+
/**
* Called by unary expressions to generate a code block that returns null if its parent returns
* null, and if not not null, use `f` to generate the expression.
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringOperations.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringOperations.scala
index 856f56488c..345038323d 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringOperations.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringOperations.scala
@@ -294,3 +294,24 @@ object Substring {
apply(str, pos, Literal(Integer.MAX_VALUE))
}
}
+
+/**
+ * A function that return the length of the given string expression.
+ */
+case class StringLength(child: Expression) extends UnaryExpression with ExpectsInputTypes {
+ override def dataType: DataType = IntegerType
+ override def expectedChildTypes: Seq[DataType] = Seq(StringType)
+
+ override def eval(input: Row): Any = {
+ val string = child.eval(input)
+ if (string == null) null else string.asInstanceOf[UTF8String].length
+ }
+
+ override def toString: String = s"length($child)"
+
+ override def genCode(ctx: CodeGenContext, ev: GeneratedExpressionCode): String = {
+ defineCodeGen(ctx, ev, c => s"($c).length()")
+ }
+}
+
+
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/StringFunctionsSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/StringFunctionsSuite.scala
index 2e81296c4e..d363e63154 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/StringFunctionsSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/StringFunctionsSuite.scala
@@ -215,4 +215,16 @@ class StringFunctionsSuite extends SparkFunSuite with ExpressionEvalHelper {
evaluate("abbbbc" rlike regEx, create_row("**"))
}
}
+
+ test("length for string") {
+ val regEx = 'a.string.at(0)
+ checkEvaluation(StringLength(Literal("abc")), 3, create_row("abdef"))
+ checkEvaluation(StringLength(regEx), 5, create_row("abdef"))
+ checkEvaluation(StringLength(regEx), 0, create_row(""))
+ checkEvaluation(StringLength(regEx), null, create_row(null))
+ // TODO currently bug in codegen, let's temporally disable this
+ // checkEvaluation(StringLength(Literal.create(null, StringType)), null, create_row("abdef"))
+ }
+
+
}
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
index b3fc1e6cd9..083f6b6bce 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
@@ -37,6 +37,7 @@ import org.apache.spark.util.Utils
* @groupname normal_funcs Non-aggregate functions
* @groupname math_funcs Math functions
* @groupname window_funcs Window functions
+ * @groupname string_funcs String functions
* @groupname Ungrouped Support functions for DataFrames.
* @since 1.3.0
*/
@@ -1317,6 +1318,23 @@ object functions {
*/
def toRadians(columnName: String): Column = toRadians(Column(columnName))
+ //////////////////////////////////////////////////////////////////////////////////////////////
+ // String functions
+ //////////////////////////////////////////////////////////////////////////////////////////////
+
+ /**
+ * Computes the length of a given string value
+ * @group string_funcs
+ * @since 1.5.0
+ */
+ def strlen(e: Column): Column = StringLength(e.expr)
+
+ /**
+ * Computes the length of a given string column
+ * @group string_funcs
+ * @since 1.5.0
+ */
+ def strlen(columnName: String): Column = strlen(Column(columnName))
//////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala
index b93ad39f5d..171a2151e6 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala
@@ -109,4 +109,24 @@ class DataFrameFunctionsSuite extends QueryTest {
testData2.select(bitwiseNOT($"a")),
testData2.collect().toSeq.map(r => Row(~r.getInt(0))))
}
+
+ test("length") {
+ checkAnswer(
+ nullStrings.select(strlen($"s"), strlen("s")),
+ nullStrings.collect().toSeq.map { r =>
+ val v = r.getString(1)
+ val l = if (v == null) null else v.length
+ Row(l, l)
+ })
+
+ checkAnswer(
+ nullStrings.selectExpr("length(s)"),
+ nullStrings.collect().toSeq.map { r =>
+ val v = r.getString(1)
+ val l = if (v == null) null else v.length
+ Row(l)
+ })
+ }
+
+
}
--
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