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https://issues.apache.org/jira/browse/ARROW-8813?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dominic Dennenmoser updated ARROW-8813:
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Description:
I think it would be reasonable to implement an interface to the {{tidyr}}
package. The implementation would allow to lazily process ArrowTables before
put it back into the memory. However, currently you need to collect the table
first before applying tidyr methods. The following code chunk shows an example
routine:
{code:r}
library(magrittr)
arrow_table <- arrow::read_feather("table.feather", as_data_frame = FALSE)
nested_df <-
arrow_table %>%
dplyr::select(ID, 4:7, Value) %>%
dplyr::filter(Value >= 5) %>%
dplyr::group_by(ID) %>%
dplyr::collect() %>%
tidyr::nest(){code}
The main focus might be the following three methods:
* {{tidyr::[un]nest()}},
* {{tidyr::pivot_[longer|wider]()}}, and
* {{tidyr::seperate()}}.
I suppose the last two can be fairly quickly implemented, but {{tidyr::nest()}}
and {{tidyr::unnest()}} cannot be implement before [conversion to
List<Struct>|ARROW-8779] will be accessible.
was:
I think it would be reasonable to implement an interface to the {{tidyr}}
package. The implementation would allow to lazily process ArrowTables before
put it back into the memory. However, currently you need to collect the table
first before applying tidyr methods. The following code chunk shows an example
routine:
{code:r}
library(magrittr)
arrow_table <- arrow::read_feather("table.feather", as_data_frame = FALSE)
nested_df <-
arrow_table %>%
dplyr::select(ID, 4:7, Value) %>%
dplyr::filter(Value >= 5) %>%
dplyr::group_by(ID) %>%
dplyr::collect() %>%
tidyr::nest(){code}
The main focus might be the following three methods:
* {{tidyr::[un]nest()}},
* {{tidyr::pivot_[longer|wider]()}}, and
* {{tidyr::seperate()}}.
I suppose the last two can be fairly quickly implemented, but {{tidyr::nest()}}
and {{tidyr::unnest()}} cannot be implement before conversion to List<Struct>
will be accessible.
> [R] Implementing tidyr interface
> --------------------------------
>
> Key: ARROW-8813
> URL: https://issues.apache.org/jira/browse/ARROW-8813
> Project: Apache Arrow
> Issue Type: Improvement
> Components: R
> Reporter: Dominic Dennenmoser
> Priority: Major
> Labels: extension, feature, improvement
>
> I think it would be reasonable to implement an interface to the {{tidyr}}
> package. The implementation would allow to lazily process ArrowTables before
> put it back into the memory. However, currently you need to collect the table
> first before applying tidyr methods. The following code chunk shows an
> example routine:
> {code:r}
> library(magrittr)
> arrow_table <- arrow::read_feather("table.feather", as_data_frame = FALSE)
> nested_df <-
> arrow_table %>%
> dplyr::select(ID, 4:7, Value) %>%
> dplyr::filter(Value >= 5) %>%
> dplyr::group_by(ID) %>%
> dplyr::collect() %>%
> tidyr::nest(){code}
> The main focus might be the following three methods:
> * {{tidyr::[un]nest()}},
> * {{tidyr::pivot_[longer|wider]()}}, and
> * {{tidyr::seperate()}}.
> I suppose the last two can be fairly quickly implemented, but
> {{tidyr::nest()}} and {{tidyr::unnest()}} cannot be implement before
> [conversion to List<Struct>|ARROW-8779] will be accessible.
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