Github user crafty-coder commented on a diff in the pull request:
https://github.com/apache/spark/pull/22031#discussion_r208387111
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/higherOrderFunctions.scala
---
@@ -442,3 +442,93 @@ case class ArrayAggregate(
override def prettyName: String = "aggregate"
}
+
+/**
+ * Transform elements in an array using the transform function. This is
similar to
+ * a `map` in functional programming.
+ */
+// scalastyle:off line.size.limit
+@ExpressionDescription(
+ usage = "_FUNC_(expr, func) - Merges the two given arrays, element-wise,
into a single array using function. If one array is shorter, nulls are appended
at the end to match the length of the longer array, before applying function.",
+ examples = """
+ Examples:
+ > SELECT _FUNC_(array(1, 2, 3), x -> x + 1);
--- End diff --
The examples are not accurate.
You could something like:
```
> SELECT _FUNC_(array(1, 2, 3), array('a', 'b', 'c'), (x, y) -> (y, x));
array(('a', 1), ('b', 3), ('c', 5))
> SELECT _FUNC_(array(1, 2), array(3, 4), (x, y) -> x + y));
array(4, 6)
> SELECT _FUNC_(array('a', 'b', 'c'), array('d', 'e', 'f'), (x, y) ->
concat(x, y));
array('ad', 'be', 'cf')
```
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