Github user HyukjinKwon commented on a diff in the pull request: https://github.com/apache/spark/pull/21250#discussion_r186411141 --- Diff: docs/sparkr.md --- @@ -663,3 +663,7 @@ You can inspect the search path in R with [`search()`](https://stat.ethz.ch/R-ma - The `stringsAsFactors` parameter was previously ignored with `collect`, for example, in `collect(createDataFrame(iris), stringsAsFactors = TRUE))`. It has been corrected. - For `summary`, option for statistics to compute has been added. Its output is changed from that from `describe`. - A warning can be raised if versions of SparkR package and the Spark JVM do not match. + +## Upgrading to SparkR 2.3.1 and above + + - In SparkR 2.3.0 and earlier, the `start` parameter of `substr` method was wrongly subtracted by one, previously. In other words, the index specified by `start` parameter was considered as 0-base. This can lead to inconsistent substring results and also does not match with the behaviour with `substr` in R. In version 2.3.1 and later, it has been fixed so the `start` parameter of `substr` method is now 1-base. As an example, `substr(lit('abcdef'), 2, 4))` would result to `abc` in SparkR 2.3.0, and the result would be `bcd` in SparkR 2.3.1. --- End diff -- like .. `collect(select(createDataframe(iris), substr(lit('abcdef'), 2, 4))))`
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