Skip to contents

Format character vectors into search terms for openFDA API queries

Source: R/format_search_term.R
format_search_term.Rd

This function is a helper for constructing search queries. Whilst it handles some of the available formatting for openFDA APIs, it does not recapture all of the search term syntax available to you. To get a full appreciation of the openFDA search syntax, see https://open.fda.gov/apis/advanced-syntax/.

Usage

format_search_term(search, exact = TRUE, mode = "or")

Arguments

A character vector of length 1 or more. If scalar and unnamed, it will be assumed that you have already formatted your search string to work with the API. If named, the vector will be collapsed to include your various search terms, separated by AND or OR terms based on the value of operator.

exact

A single-length logical vector. When TRUE (the default), individual search terms will be surrounded with double quotes (""). Set exact to FALSE if your search term contains multiple words to be searched on, e.g. c("openfda.generic_name" = "losartan+candesartan").

This parameter only applies if search is a named character vector.

mode

A single-length character vector, which defines how searches in multiple fields should be combined. By default ("or") they will be combined with an 'OR' operator, but you can make an 'AND' operator be used instead ("and"). This argument is case-sensitive and will throw an error if mode is not one of either "and" or "or".

This parameter only applies if search is a named character vector.

Value

A character vector of the S3 class <AsIS>, with a formatted search term which can be supplied to openFDA().

Note

This function does not check that you're providing accurate field names or search terms. It is up to you to make sure you've provided correctly spelt fields and search terms.

See also

  • format_sort_term() performs similar formatting for the sort component of an openFDA query.

  • I() generates vectors with the <AsIs> S3 class.

  • httr2::req_url() documents why I() is applied to the output of this function.

Examples

# Provide a formatted search string and the function will do no formatting
format_search_term("openfda.generic_name:verapamil")
#> [1] "openfda.generic_name:verapamil"

# Provide a named vector and the function will format it for you
format_search_term(c("openfda.generic_name" = "verapamil"))
#> [1] "openfda.generic_name:%22verapamil%22"

# If providing multiple elements in your search term, use `exact = FALSE`
# to prevent the function from surrounding the term with double quotes.
format_search_term(c("openfda.generic_name" = "verapamil+amlodipine"),
                   exact = FALSE)
#> [1] "openfda.generic_name:verapamil+amlodipine"

# Provide a longer named vector and function will merge these with an OR
# operator
format_search_term(c("openfda.generic_name" = "verapamil",
                     "openfda.manufacturer_name" = "glaxo*"))
#> [1] "openfda.generic_name:%22verapamil%22+openfda.manufacturer_name:%22glaxo%2A%22"

# Or you can set the `mode` argument to merge your search terms with an AND
# operator
format_search_term(c("openfda.generic_name" = "verapamil",
                     "openfda.manufacturer_name" = "glaxo*"),
                   mode = "and")
#> [1] "openfda.generic_name:%22verapamil%22+AND+openfda.manufacturer_name:%22glaxo%2A%22"