cloud-fan commented on a change in pull request #35352:
URL: https://github.com/apache/spark/pull/35352#discussion_r832169814
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
##########
@@ -2943,3 +2943,87 @@ case class Sentences(
copy(str = newFirst, language = newSecond, country = newThird)
}
+
+/**
+ * Splits a given string by a specified delimiter.
+ */
+case class SplitByDelimiter(
+ str: Expression,
+ delimiter: Expression)
+ extends BinaryExpression with NullIntolerant {
+ override def dataType: DataType = ArrayType(StringType, containsNull = false)
+ override def left: Expression = str
+ override def right: Expression = delimiter
+
+ override def nullSafeEval(string: Any, delimiter: Any): Any = {
+ val strings = {
+ // if delimiter is empty string, skip the regex based splitting directly
as regex
+ // treats empty string as matching anything, thus use the input directly.
+ if (delimiter.asInstanceOf[UTF8String].numBytes() == 0) {
+ Array(string)
+ } else {
+ string.asInstanceOf[UTF8String].splitSQL(
+ delimiter.asInstanceOf[UTF8String], -1)
+ }
+ }
+ new GenericArrayData(strings.asInstanceOf[Array[Any]])
+ }
+
+ override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+ val arrayClass = classOf[GenericArrayData].getName
+ nullSafeCodeGen(ctx, ev, (str, delimiter) => {
+ if (delimiter.asInstanceOf[UTF8String].numBytes() == 0) {
+ s"""${ev.value} = Array($str)""".stripMargin
+ } else {
+ // Array in java is covariant, so we don't need to cast UTF8String[]
to Object[].
+ s"""${ev.value} = new
$arrayClass($str.splitSQL($delimiter,-1));""".stripMargin
+ }
+ })
+ }
+
+ override protected def withNewChildrenInternal(
+ newFirst: Expression, newSecond: Expression): SplitByDelimiter =
+ copy(str = newFirst, delimiter = newSecond)
+}
+
+/**
+ * Splits a given string by a specified delimiter and returns the requested
part.
+ * If any input is null, returns null.
+ * If index is out of range of split parts, return empty string.
+ * If index is 0, throws an ArrayIndexOutOfBoundsException.
+ */
+@ExpressionDescription(
+ usage =
+ """
+ _FUNC_(str, delimiter, partNum) - Splits `str` by delimiter and return
+ requested part of the split (1-based). If any input is null, returns
null.
+ if `partNum` is out of range of split parts, returns null. If `partNum`
is 0,
+ throws an error. If `partNum` is negative, the parts are counted
backward from the
+ end of the string. If the `delimiter` is an empty string, the `str` is
not split.
+ """,
+ examples =
+ """
+ Examples:
+ > SELECT _FUNC_('11.12.13', '.', 3);
+ 13
+ """,
+ since = "3.3.0",
+ group = "string_funcs")
+case class SplitPart (
+ str: Expression,
+ delimiter: Expression,
+ partNum: Expression)
+ extends RuntimeReplaceable {
+ override lazy val replacement: Expression =
+ ElementAt(SplitByDelimiter(str, delimiter), partNum,
Some(Literal.create("", StringType)),
+ SQLConf.get.ansiEnabled)
Review comment:
we should pass `false` instead of `SQLConf.get.ansiEnabled`, because we
want `ElementAt` to return empty string for out of bound value instead of
failing.
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