Github user maropu commented on a diff in the pull request:
https://github.com/apache/spark/pull/22227#discussion_r213540571
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/regexpExpressions.scala
---
@@ -229,33 +229,59 @@ case class RLike(left: Expression, right: Expression)
extends StringRegexExpress
/**
- * Splits str around pat (pattern is a regular expression).
+ * Splits str around pattern (pattern is a regular expression).
*/
@ExpressionDescription(
- usage = "_FUNC_(str, regex) - Splits `str` around occurrences that match
`regex`.",
+ usage = "_FUNC_(str, regex, limit) - Splits `str` around occurrences
that match `regex`" +
+ " and returns an array of at most `limit`",
+ arguments = """
+ Arguments:
+ * str - a string expression to split.
+ * pattern - a string representing a regular expression. The pattern
string should be a
+ Java regular expression.
+ * limit - an integer expression which controls the number of times
the pattern is applied.
+
+ limit > 0:
+ The resulting array's length will not be more than `limit`, and
the resulting array's
+ last entry will contain all input beyond the last matched
pattern.
+
+ limit < 0:
+ `pattern` will be applied as many times as possible, and the
resulting
+ array can be of any size.
+
+ limit = 0:
+ `pattern` will be applied as many times as possible, the
resulting array can
+ be of any size, and trailing empty strings will be discarded.
+ """,
--- End diff --
How about this formatting?;
```
function_desc | Extended Usage:
Arguments:
* str - a string expression to split.
* pattern - a string representing a regular expression. The pattern
string should be a
Java regular expression.
* limit - an integer expression which controls the number of times
the pattern is applied.
limit > 0: The resulting array's length will not be more than
`limit`, and the resulting array's
last entry will contain all input beyond the last
matched pattern.
limit < 0: `pattern` will be applied as many times as possible, and
the resulting
array can be of any size.
limit = 0: `pattern` will be applied as many times as possible, the
resulting array can
be of any size, and trailing empty strings will be
discarded.
Examples:
> SELECT split('oneAtwoBthreeC', '[ABC]');
["one","two","three",""]
> SELECT split('oneAtwoBthreeC', '[ABC]', 0);
["one","two","three"]
> SELECT split('oneAtwoBthreeC', '[ABC]', 2);
["one","twoBthreeC"]
```
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