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https://issues.apache.org/jira/browse/ARROW-6819?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16947079#comment-16947079
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Neal Richardson commented on ARROW-6819:
----------------------------------------
A {{tibble}} is a {{data.frame}}, just with additional attributes that affect
how it prints. These additional attributes are added to the data.frame that
{{arrow}} returns, but you only notice them when you're using the tibble
package. When you load {{sparklyr}}, the tibble namespace is loaded, so the
tibble print method is found and used.
This behavior is noted in the new package vignette:
[https://github.com/apache/arrow/blob/master/r/vignettes/arrow.Rmd#L15]
{{as_data_frame}} governs whether you get an R data.frame/tibble or whether the
data is kept in Arrow memory as an arrow::Table
[https://github.com/apache/arrow/blob/master/r/R/parquet.R#L27-L28]
> arrow::read_parquet ignores as_data_frame when sparklyr package is attached
> ---------------------------------------------------------------------------
>
> Key: ARROW-6819
> URL: https://issues.apache.org/jira/browse/ARROW-6819
> Project: Apache Arrow
> Issue Type: Bug
> Components: R
> Affects Versions: 0.15.0
> Environment: R version 3.6.1 (2019-07-05) on x86_64, darwin15.6.0
> (Mac OS 10.13.4)
> Reporter: Ryan Patrick Kyle
> Priority: Major
>
> I am currently using v0.15.0 of the arrow package, installed from source
> using CRAN. I also have v1.0.4 of the sparklyr package installed. While
> attempting to read in Parquet data with both packages attached, the
> read_parquet function appears to ignore the as_data_frame argument (which
> defaults to TRUE).
> [https://github.com/apache/arrow/blob/3d55122c56a508894823a1b79bca71f519fdd52f/r/R/parquet.R#L35-L47]
> I am not certain, but I suspect the issue may be in the way
> Table__to_dataframe coerces Arrow Table objects into tibbles, since this
> statement appears also to produce a tibble (I expected a data.frame to be
> returned):
> {{arrow:::Table__to_dataframe(tab, use_threads=FALSE)}}
>
> A reproducible example follows.
>
> {{# This does work as expected, returns data.frame}}
> {{library(arrow)}}
> {{temp <- tempfile()}}
>
> {{download.file("https://github.com/Teradata/kylo/blob/master/samples/sample-data/parquet/userdata1.parquet?raw=true";,
> temp)}}
> {{read_parquet(temp, as_data_frame=TRUE)}}
> {{# This does not work as expected, returns tibble}}
> {{library(sparklyr)}}
> {{read_parquet(temp, as_data_frame=TRUE)}}{{ }}
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