Get/Add subject(s) to a dataset — subject • dataset

Add one or more subject terms to the dataset's metadata.

Usage

subject(x)

subject(x, overwrite = FALSE) <- value

subject_create(
  term,
  subjectScheme = NA_character_,
  schemeURI = NA_character_,
  valueURI = NA_character_
)

Arguments

x: An R object
overwrite: Defaults to FALSE, in which case new subject(x) <- "Subject" calls are binding further Subjects to the already set Subject properties.
value: Subject terms, or a Subject object created by subject_create.
term: A term, or a character vector of multiple terms.
subjectScheme: The scheme to which the term corresponds. If there are multiple terms, provide the subjectScheme(s) in the same order. Optional.
schemeURI: The URI(s) of the subject identifier scheme. If there are multiple terms, provide the schemeURIs in the same order as the terms. Optional.
valueURI: The URI of the subject term. If there are multiple terms, provide the valueURIs in the same order as the terms. Optional.

Value

The subjects as a data.frame of terms

Details

In the Dublin Core elements, dct::subject is defined Typically, the subject will be represented using keywords, key phrases, or classification codes. It is recommended as a best practice to use a controlled vocabulary.
In DataCite, subjects are defined as key phrases from a controlled library.

Examples

x <- data.frame( geo = c("AL", "MK"),
                value = c(1,2))
my_subject <- subject_create (
                  term = c("R (Computer program language)",
                           "Questionnaires--Computer programs"),
                  subjectScheme = rep("LC Subject Headings", 2),
                  schemeURI = rep("http://id.loc.gov/authorities/subjects",2),
                  valueURI = c("https://id.loc.gov/authorities/subjects/sh2002004407.html",
                               "http://id.worldcat.org/fast/1085693/")
)
 subject(x) <- my_subject
 subject(x)
#>                                term       subjectScheme
#> 1     R (Computer program language) LC Subject Headings
#> 2 Questionnaires--Computer programs LC Subject Headings
#>                                schemeURI
#> 1 http://id.loc.gov/authorities/subjects
#> 2 http://id.loc.gov/authorities/subjects
#>                                                    valueURI
#> 1 https://id.loc.gov/authorities/subjects/sh2002004407.html
#> 2                      http://id.worldcat.org/fast/1085693/

 y <- data.frame()
 subject(y) <- "R (Computer program language)"
 subject(y) <- "Questionnaires--Computer programs"
 subject(y)
#>                                term subjectScheme schemeURI valueURI
#> 1     R (Computer program language)          <NA>      <NA>     <NA>
#> 2 Questionnaires--Computer programs          <NA>      <NA>     <NA>