Extract prepositions from row and column labels — get

This function extracts prepositions from a list of row and column labels. The list has outer structure of the number of labels and an inner structure of each prepositional phrase in the specific label.

Usage

get_prepositions(
  labels,
  inf_notation = TRUE,
  notation = RCLabels::notations_list,
  choose_most_specific = FALSE,
  prepositions = RCLabels::prepositions_list
)

Arguments

labels: The row and column labels from which prepositional phrases are to be extracted.
inf_notation: A boolean that tells whether to infer notation for x. Default is TRUE. See infer_notation() for details.
notation: The notation type to be used when extracting prepositions. Default is RCLabels::notations_list, meaning that the notation is inferred using infer_notation().
choose_most_specific: A boolean that tells whether to choose the most specific notation from notation when inferring notation. Default is FALSE so that a less specific notation can be inferred. In combination with RCLabels::notations_list, the default value of FALSE means that RCLabels::bracket_notation will be selected instead of anything more specific, such as RCLabels::from_notation.
prepositions: A vector of strings to be treated as prepositions. Note that a space is appended to each word internally, so, e.g., "to" becomes "to ". Default is RCLabels::prepositions_list.

Value

A list of prepositions.

Details

If labels are in the form of from_notation, to_notation or similar, it is probably best to give bracket_notation in the notation argument. Providing from_notation, to_notation or similar in the notation argument will lead to empty results. The preposition is discarded when extracting the suffix, yielding empty strings for the prepositions.

Examples

get_prepositions(c("a [of b into c]", "d [-> e of f]"))
#> $prepositions
#> [1] "of"   "into"
#> 
#> $prepositions
#> [1] "->" "of"
#> 
get_prepositions(c("a [of b]", "d [-> e of f]"),
                 inf_notation = FALSE,
                 notation = bracket_notation)
#> $prepositions
#> [1] "of"
#> 
#> $prepositions
#> [1] "->" "of"
#> 
# Best to *not* specify notation by the preposition,
# as the result will be empty strings.
# Rather, give the notation as `bracket_notation`
# as shown above, or infer the notation
# as shown below.
get_prepositions(c("a [of b]", "d [-> e of f]"),
                 inf_notation = TRUE)
#> $prepositions
#> [1] "of"
#> 
#> $prepositions
#> [1] "->" "of"
#> 
# The suffix is extracted, and the preposition
# is lost before looking for the preposition.
get_prepositions(c("a [of b]", "d [of f]"),
                 inf_notation = FALSE,
                 notation = of_notation)
#> $prepositions
#> [1] ""
#> 
#> $prepositions
#> [1] ""
#>