Retrieves only the total number of records matching a query, without
downloading them. This is the inexpensive way to size a retrieval before
committing quota. The count can guide how to partition a scopus_plan(), or
simply report how large a topic is.
Usage
scopus_count(
query,
years = NULL,
field = NULL,
view = c("STANDARD", "COMPLETE"),
api_key = NULL,
inst_token = NULL
)Arguments
- query
Character scalar. The base search expression.
- years
Optional integer vector of publication years to restrict to.
- field
Optional 'Scopus' field tag to wrap the query in (see
scopus_plan()).- view
Either
"STANDARD"or"COMPLETE".- api_key, inst_token
Optional credentials, resolved by default from options or environment variables (see
scopus_has_key()).
Value
A single number giving the total number of matching records, or NA
when the API reports no total. It is returned as a double so that very large
totals are represented exactly rather than overflowing, with the parsed
quota (see scopus_quota()) attached as the quota attribute so a workflow
can pace itself off a count.
API access
This function performs a network request and therefore requires a valid API
key and internet access. When no key is configured it raises a
scopus_error_no_key condition, and other failures raise typed scopus_error
subclasses such as scopus_error_rate_limit. A tryCatch() around the call
lets a workflow handle these gracefully.