Github user gatorsmile commented on a diff in the pull request:
https://github.com/apache/spark/pull/12646#discussion_r114264807
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
---
@@ -461,68 +462,270 @@ case class FindInSet(left: Expression, right:
Expression) extends BinaryExpressi
}
/**
- * A function that trim the spaces from both ends for the specified string.
+ * A function that trim the spaces or a character from both ends for the
specified 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 trimChar FROM str) - Remove the leading and trailing
trimChar from `str`
+ _FUNC_(LEADING trimChar FROM str) - Remove the leading trimChar from
`str`
+ _FUNC_(TRAILING trimChar FROM str) - Remove the trailing trimChar from
`str`
+ """,
extended = """
+ Arguments:
+ str - a string expression
+ trimChar - the trim character
+ BOTH, FROM - these are keyword to specify for trim character from
both side of the string
+ LEADING, FROM - these are keyword to specify for trim character from
left side of the string
+ TRAILING, FROM - these are keyword to specify for trim character
from right side of the string
Examples:
> SELECT _FUNC_(' SparkSQL ');
SparkSQL
+ > SELECT _FUNC_(BOTH 'S' FROM 'SSparkSQLS');
+ parkSQL
+ > SELECT _FUNC_(LEADING 'S' FROM 'SSparkSQLS');
+ parkSQLS
+ > SELECT _FUNC_(TRAILING 'S' FROM 'SSparkSQLS');
+ SSparkSQL
""")
-case class StringTrim(child: Expression)
- extends UnaryExpression with String2StringExpression {
+case class StringTrim(children: Seq[Expression])
+ extends Expression with ImplicitCastInputTypes {
- def convert(v: UTF8String): UTF8String = v.trim()
+ require(children.size <= 2 && children.nonEmpty,
+ s"$prettyName requires at least one argument and no more than two.")
+
+ override def dataType: DataType = StringType
+ override def inputTypes: Seq[AbstractDataType] =
Seq.fill(children.size)(StringType)
+
+ override def nullable: Boolean = children.exists(_.nullable)
+ override def foldable: Boolean = children.forall(_.foldable)
override def prettyName: String = "trim"
+ override def eval(input: InternalRow): Any = {
+ val inputs = children.map(_.eval(input).asInstanceOf[UTF8String])
+ if (inputs(0) != null) {
+ if (children.size == 1) {
+ return inputs(0).trim()
+ } else if (inputs(1) != null) {
+ if (inputs(0).numChars > 1) {
+ throw new AnalysisException(s"Trim character '${inputs(0)}' can
not be greater than " +
+ s"1 character.")
+ } else {
+ return inputs(1).trim(inputs(0))
+ }
+ }
+ }
+ null
+ }
+
override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
- defineCodeGen(ctx, ev, c => s"($c).trim()")
+ if (children.size == 2 &&
+ (! children(0).isInstanceOf[Literal] || children(0).toString.length
> 1)) {
+ throw new AnalysisException(s"The trimming parameter should be
Literal " +
+ s"and only one character.") }
+
+ val evals = children.map(_.genCode(ctx))
+ val inputs = evals.map { eval =>
+ s"${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)});""".stripMargin
+ }
+ ev.copy(evals.map(_.code).mkString("\n") +
+ s"""
+ boolean ${ev.isNull} = false;
+ ${getTrimFunction};
+ if (${ev.value} == null) {
+ ${ev.isNull} = true;
+ }
+ """)
+ }
+
+ override def sql: String = {
+ if (children.size == 1) {
+ val childrenSQL = children.map(_.sql).mkString(", ")
+ s"$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 left end for given string.
+ * A function that trim the spaces or a character from left end for given
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_(trimChar, str) - Remove the leading trimChar from `str`
--- End diff --
Oracle:
https://docs.oracle.com/cd/B19306_01/server.102/b14200/functions083.htm
Postgres: https://www.postgresql.org/docs/9.1/static/functions-string.html
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