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[SPARK-23291][SQL][R][BRANCH-2.3] R's substr should not reduce starting position by 1 when calling Scala API - #21250
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…by 1 when calling Scala API ## What changes were proposed in this pull request? Seems R's substr API treats Scala substr API as zero based and so subtracts the given starting position by 1. Because Scala's substr API also accepts zero-based starting position (treated as the first element), so the current R's substr test results are correct as they all use 1 as starting positions. ## How was this patch tested? Modified tests. Author: Liang-Chi Hsieh <viirya@gmail.com> Closesapache#20464 from viirya/SPARK-23291.
HyukjinKwon
commented
May 6, 2018
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cc @cloud-fan, @yanboliang, @felixcheung and @viirya. |
SparkQA
commented
May 6, 2018
Test build #90272 has finished for PR 21250 at commit
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| - 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 Spark 2.3.1 and above |
| ## Upgrading to Spark 2.3.1 and above | ||
| - 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. It has been fixed so the `start` parameter of `substr` method is now 1-base, e.g., therefore to get the same result as `substr(df$a, 2, 5)`, it should be changed to `substr(df$a, 1, 4)`. |
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we should mention the version more explicitly, e.g.
In SparkR 2.3.0 and earlier, the `start` parameter ... In version 2.3.1 and later, ... As an example, `substr(lit('abcdef'), 2, 5)` would result to `abc` in SparkR 2.3.0, and in SparkR 2.3.1, the result would be ...
SparkQA
commented
May 7, 2018
Test build #90310 has finished for PR 21250 at commit
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| ## 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. |
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please make sure substr(lit('abcdef'), 2, 4)) is valid in Spark R, I didn't check it with Spark R document when writing it...
MemberAuthor
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like .. collect(select(createDataFrame(iris), substr(lit('abcdef'), 2, 4)))
MemberAuthor
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Just double checked:
master:
> collect(select(createDataFrame(iris), substr(lit('abcdef'), 2, 4)))
...
1 bcd
...
2.3.0:
> collect(select(createDataFrame(iris), substr(lit('abcdef'), 2, 4)))
...
1 abc
...
| ## 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. |
Contributor
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a little simplification:
the `start` parameter of `substr` method was wrongly subtracted by one and considered as 0-based. This leads to ...
cloud-fan
commented
May 7, 2018
Contributor
LGTM |
SparkQA
commented
May 7, 2018
Test build #90325 has finished for PR 21250 at commit
|
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May 7, 2018
…ng position by 1 when calling Scala API ## What changes were proposed in this pull request? This PR backports 24b5c69 and #21249 There's no conflict but I opened this just to run the test and for sure. See the discussion in https://issues.apache.org/jira/browse/SPARK-23291 ## How was this patch tested? Jenkins tests. Author: hyukjinkwon <gurwls223@apache.org> Author: Liang-Chi Hsieh <viirya@gmail.com> Closes#21250 from HyukjinKwon/SPARK-23291-backport.
MemberAuthor
Thanks, @cloud-fan, @yanboliang, @felixcheung, @dongjoon-hyun and @viirya. |
gatorsmile
commented
May 8, 2018
Member
Thank you for writing the migration guide |
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What changes were proposed in this pull request?
This PR backports 24b5c69 and #21249
There's no conflict but I opened this just to run the test and for sure.
See the discussion in https://issues.apache.org/jira/browse/SPARK-23291
How was this patch tested?
Jenkins tests.