Given a row_id value and a result column, this function will return the tplyr_meta object associated with that 'cell'.
Arguments
- x
A built Tplyr table or a dataframe
- row_id
The row_id value of the desired cell, provided as a character string
- column
The result column of interest, provided as a character string
- ...
additional arguments
Details
If a Tplyr table is built with the metadata=TRUE option specified, then
metadata is assembled behind the scenes to provide traceability on each
result cell derived. The functions get_meta_result() and
get_meta_subset() allow you to access that metadata by using an ID provided
in the row_id column and the column name of the result you'd like to access.
The purpose is of the row_id variable instead of a simple row index is to
provide a sort resistant reference of the originating column, so the output
Tplyr table can be sorted in any order but the metadata are still easily
accessible.
The tplyr_meta object provided a list with two elements - names and
filters. The metadata contain every column from the target data.frame of the
Tplyr table that factored into the specified result cell, and the filters
contains all the necessary filters to subset to data summarized to create the
specified result cell. get_meta_subset() additionally provides a parameter to
specify any additional columns you would like to include in the returned
subset data frame.
Examples
t <- tplyr_table(mtcars, cyl) %>%
add_layer(
group_desc(hp)
)
dat <- t %>% build(metadata = TRUE)
get_meta_result(t, 'd1_1', 'var1_4')
#> tplyr_meta: 2 names, 3 filters
#> Names:
#> cyl, hp
#> Filters:
#> cyl == c("4"), TRUE, TRUE
m <- t$metadata
dat <- t$target
get_meta_result(t, 'd1_1', 'var1_4')
#> tplyr_meta: 2 names, 3 filters
#> Names:
#> cyl, hp
#> Filters:
#> cyl == c("4"), TRUE, TRUE