Check whether a query can be evaluated against a daf without error. — has_query • dafr

Check whether a query can be evaluated against a daf without error.

Usage

has_query(daf, query_string)

Arguments

daf: A DafReader.
query_string: A query string (character scalar) or a DafrQuery object produced by the query builders (e.g. Axis("cell") |> LookupVector("donor")).

Value

Logical scalar. TRUE if get_query(daf, query_string) would succeed with a non-empty result; FALSE otherwise.

Examples

d <- example_cells_daf()
has_query(d, "@ cell : donor")
#> [1] TRUE
has_query(d, "@ cell : nonexistent_property")
#> [1] FALSE