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https://issues.apache.org/jira/browse/ARROW-16641?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17541934#comment-17541934
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Vladimir commented on ARROW-16641:
----------------------------------
Thank you very much for the comprehensive answer! It's very helpful!
As I understand, {{list_parent_indices}} discards records without any flags
({{{}NULL{}}} values). Is it possible to keep the nulls? I've tried to specify
the options ({{{}skip_nulls = "false" {}}}or {{{}skip_nulls = FALSE{}}}), but
it doesn't have any effect.
{code:java}
tab <- arrow_table(
x = Array$create(list(c(1, 2), 1, NULL)),
y = Array$create(c("a", "b", "c"))
)
tab_exploded <- arrow_table(
i = call_function("list_parent_indices", tab$x, options = list(skip_nulls =
"false")),
x_flat = call_function("list_flatten", tab$x)
)
{code}
> [R] How to filter array columns?
> --------------------------------
>
> Key: ARROW-16641
> URL: https://issues.apache.org/jira/browse/ARROW-16641
> Project: Apache Arrow
> Issue Type: Wish
> Components: R
> Reporter: Vladimir
> Priority: Minor
> Fix For: 8.0.0
>
>
> In the parquet data we have, there is a column with the array data type
> ({*}list<array_element <string>>{*}), which flags records that have different
> issues. For each record, multiple values could be stored in the column. For
> example, `{_}[A, B, C]{_}`.
> I'm trying to perform a data filtering step and exclude some flagged records.
> Filtering is trivial for the regular columns that contain just a single
> value. E.g.,
> {code:java}
> flags_to_exclude <- c("A", "B")
> datt %>% filter(! col %in% flags_to_exclude)
> {code}
> Given the array column, is it possible to exclude records with at least one
> of the flags from `flags_to_exclude` using the arrow R package?
> I really appreciate any advice you can provide!
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