Github user kevinyu98 commented on a diff in the pull request:
https://github.com/apache/spark/pull/12646#discussion_r120243912
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
---
@@ -502,69 +503,232 @@ case class FindInSet(left: Expression, right:
Expression) extends BinaryExpressi
override def prettyName: String = "find_in_set"
}
+trait String2TrimExpression extends ImplicitCastInputTypes {
+ self: Expression =>
+
+ override def dataType: DataType = StringType
+ override def inputTypes: Seq[AbstractDataType] =
Seq.fill(children.size)(StringType)
+
+ override def nullable: Boolean = children.exists(_.nullable)
+ override def foldable: Boolean = children.forall(_.foldable)
+
+ override def sql: String = {
+ if (children.size == 1) {
+ val childrenSQL = children.map(_.sql).mkString(", ")
+ s"$prettyName($childrenSQL)"
+ } else {
+ val trimSQL = children(0).map(_.sql).mkString(", ")
+ val tarSQL = children(1).map(_.sql).mkString(", ")
+ s"$prettyName($trimSQL, $tarSQL)"
+ }
+ }
+}
+
/**
- * A function that trim the spaces from both ends for the specified string.
- */
+ * A function that takes a character string, removes the leading and/or
trailing characters matching with the characters
+ * in the trim string, returns the new string. If BOTH and trimStr
keywords are not specified, it defaults to remove
+ * space character from both ends.
+ * trimStr: A character string to be trimmed from the source string, if it
has multiple characters, the function
+ * searches for each character in the source string, removes the
characters from the source string until it
+ * encounters the first non-match character.
+ * BOTH: removes any characters from both ends of the source string that
matches characters in the trim string.
+ */
@ExpressionDescription(
- usage = "_FUNC_(str) - Removes the leading and trailing space characters
from `str`.",
+ usage = """
+ _FUNC_(str) - Removes the leading and trailing space characters from
`str`.
+ _FUNC_(BOTH trimStr FROM str) - Remove the leading and trailing
trimString from `str`
+ """,
extended = """
+ Arguments:
+ str - a string expression
+ trimString - the trim string
+ BOTH, FROM - these are keyword to specify for trim string from both
ends of the string
Examples:
> SELECT _FUNC_(' SparkSQL ');
SparkSQL
+ > SELECT _FUNC_(BOTH 'SL' FROM 'SSparkSQLS');
+ parkSQ
""")
-case class StringTrim(child: Expression)
- extends UnaryExpression with String2StringExpression {
+case class StringTrim(children: Seq[Expression])
+ extends Expression with String2TrimExpression {
- def convert(v: UTF8String): UTF8String = v.trim()
+ require(children.size <= 2 && children.nonEmpty,
+ s"$prettyName requires at least one argument and no more than two.")
override def prettyName: String = "trim"
+ // trim function can take one or two arguments.
+ // Specify one child, it is for the trim space function.
+ // Specify the two children, it is for the trim function with BOTH
option.
+ override def eval(input: InternalRow): Any = {
+ val inputs = children.map(_.eval(input).asInstanceOf[UTF8String])
+ if (inputs(0) != null) {
+ if (children.size == 1) {
+ return inputs(0).trim()
+ } else if (inputs(1) != null) {
+ return inputs(1).trim(inputs(0))
+ }
+ }
+ null
+ }
+
override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
- defineCodeGen(ctx, ev, c => s"($c).trim()")
+ if (children.size == 2 && !children(0).isInstanceOf[Literal]) {
+ throw new AnalysisException(s"The trimming parameter should be
Literal.")}
+
+ val evals = children.map(_.genCode(ctx))
+ val inputs = evals.map { eval =>
+ s"${eval.isNull} ? null : ${eval.value}"
+ }
+ val getTrimFunction = if (children.size == 1) {
+ s"UTF8String ${ev.value} = ${inputs(0)}.trim();"
+ } else {
+ s"UTF8String ${ev.value} = ${inputs(1)}.trim(${inputs(0)});"
+ }
+ ev.copy(evals.map(_.code).mkString("\n") + s"""
+ boolean ${ev.isNull} = false;
+ $getTrimFunction
+ if (${ev.value} == null) {
+ ${ev.isNull} = true;
+ }
+ """)
}
}
/**
- * A function that trim the spaces from left end for given string.
+ * A function that trims the characters from left end for a given string,
If LEADING and trimStr keywords are not
+ * specified, it defaults to remove space character from the left end.
+ * trimStr: the function removes any characters from the left end of the
source string which matches with the characters
+ * from trimStr, it stops at the first non-match character.
+ * LEADING: removes any characters from the left end of the source string
that matches characters in the trim string.
*/
@ExpressionDescription(
- usage = "_FUNC_(str) - Removes the leading and trailing space characters
from `str`.",
+ usage = """
+ _FUNC_(str) - Removes the leading space characters from `str`.
+ _FUNC_(trimStr, str) - Removes the leading string contains the
characters from the trim string
+ """,
extended = """
+ Arguments:
+ str - a string expression
+ trimStr - the trim string
Examples:
- > SELECT _FUNC_(' SparkSQL');
+ > SELECT _FUNC_(' SparkSQL ');
SparkSQL
+ > SELECT _FUNC_('Sp', 'SSparkSQLS');
+ arkSQLS
""")
-case class StringTrimLeft(child: Expression)
- extends UnaryExpression with String2StringExpression {
+case class StringTrimLeft(children: Seq[Expression])
+ extends Expression with String2TrimExpression {
- def convert(v: UTF8String): UTF8String = v.trimLeft()
+ require (children.size <= 2 && children.nonEmpty,
+ "$prettyName requires at least one argument and no more than two.")
override def prettyName: String = "ltrim"
- override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
- defineCodeGen(ctx, ev, c => s"($c).trimLeft()")
+ // ltrim function can take one or two arguments.
+ // Specify one child, it is for the ltrim space function.
+ // Specify the two children, it is for the trim function with option
LEADING.
--- End diff --
ok.
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