Github user HyukjinKwon commented on a diff in the pull request:
https://github.com/apache/spark/pull/17967#discussion_r117602233
--- Diff: mllib/src/main/scala/org/apache/spark/ml/feature/RFormula.scala
---
@@ -38,29 +38,35 @@ import org.apache.spark.sql.types._
private[feature] trait RFormulaBase extends HasFeaturesCol with
HasLabelCol {
/**
- * Param for how to order labels of string column. The first label after
ordering is assigned
- * an index of 0.
- * Options are:
- * - 'frequencyDesc': descending order by label frequency (most
frequent label assigned 0)
- * - 'frequencyAsc': ascending order by label frequency (least
frequent label assigned 0)
- * - 'alphabetDesc': descending alphabetical order
- * - 'alphabetAsc': ascending alphabetical order
- * Default is 'frequencyDesc'.
- * When the ordering is set to 'alphabetDesc', `RFormula` drops the same
category as R
- * when encoding strings.
+ * Param for how to order categories of a FEATURE string column used by
`StringIndexer`.
+ * The last category after ordering is dropped when encoding strings.
+ * The options are explained using an example string: 'b', 'a', 'b',
'a', 'c', 'b'
+ * |
+ * | Option | Category mapped to 0 by StringIndexer | Category dropped
by RFormula
--- End diff --
BTW, it looks hidden in the API documentation. My suggestion is prose with
simple `-` or resembling any other formats in this package if there are similar
instances.
Probably, it would be fine if the current format as is looks okay to you
@felixcheung.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
