Add a granularity_geo column to a data set

Derives the geographic granularity label from the location_code column. Adds the label as a new granularity_geo column, and changes x in place. When location_reference is NULL, the granularity comes from the location code prefix. When you supply a reference table, the granularity comes from that table.

Usage

add_granularity_geo_to_data_set(x, location_reference = NULL)

Arguments

x

A data.table with a column named location_code. Only a data.table method exists, so any other class raises "no applicable method".

location_reference

A data.table with columns location_code and granularity_geo to use for lookup. When NULL (default), granularity comes from the location code prefix (e.g. "county_nor03" -> "county"). Its location_code values SHOULD be unique. A code that appears twice in the reference produces more labels than x has rows. The assignment then fails with "Supplied N items to be assigned to M items of column 'granularity_geo'". nor_locations_names() holds one such code today, "lab_nor084467", which two laboratories share.

Value

x, invisibly, with the granularity_geo column added or updated.

See also

vignette("csdata", package = "csdata"), which calls this function on a worked example. location_code_to_granularity_geo() returns the same labels as a vector instead of writing them onto x.

Other data set column adders: add_iso3_to_data_set()

Examples

library(data.table)
#> 
#> Attaching package: ‘data.table’
#> The following object is masked from ‘package:base’:
#> 
#>     %notin%
data <- data.table(location_code = c("nation_nor", "county_nor03", "blah"))
csdata::add_granularity_geo_to_data_set(data)
print(data)
#>    location_code granularity_geo
#>           <char>          <char>
#> 1:    nation_nor          nation
#> 2:  county_nor03          county
#> 3:          blah            blah

library(data.table)
data <- data.table(location_code = c("nation_nor", "county_nor03", "blah"))
csdata::add_granularity_geo_to_data_set(data, location_reference = csdata::nor_locations_names())
print(data)
#>    location_code granularity_geo
#>           <char>          <char>
#> 1:    nation_nor          nation
#> 2:  county_nor03          county
#> 3:          blah            <NA>