romainfrancois commented on pull request #8122: URL: https://github.com/apache/arrow/pull/8122#issuecomment-697227723
I added some tests for `ReadRowGroup(s)()` and clarified about 0-based. I'm getting a weird error in some cases with `ReadRowGroups()`: ``` r library(arrow, warn.conflicts = FALSE) tab <- Table$create(x = 1:100) tf <- tempfile() write_parquet(tab, tf, chunk_size = 10) reader <- ParquetFileReader$create(tf) # sensible error reader$ReadRowGroups(-2) #> Error in parquet___arrow___FileReader__ReadRowGroups1(self, row_groups): Invalid: Some index in row_group_indices is -2, which is either < 0 or >= num_row_groups(10) #> In /Users/romainfrancois/git/apache/arrow/cpp/src/parquet/arrow/reader.cc, line 842, code: BoundsCheck(row_groups, column_indices) # weird error reader$ReadRowGroups(c(0, -2)) #> Error in parquet___arrow___FileReader__ReadRowGroups1(self, row_groups): IOError: The file only has 0 columns, requested metadata for column: 0 #> In /Users/romainfrancois/git/apache/arrow/cpp/src/parquet/arrow/reader.cc, line 873, code: final_status ``` <sup>Created on 2020-09-23 by the [reprex package](https://reprex.tidyverse.org) (v0.3.0.9001)</sup> ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
