Construct a Data Count Function

It is often faster to fetch counts of data, rather than the entire dataset. If your fnFetchData() function is already fast, however, this function allows you to construct a simple data counter from your data fetcher.

Usage

ConstructDataCounter(fnFetchData)

Arguments

fnFetchData

function A function that takes a strDomainID argument and optional strGroupID, strGroupLevel, strSubjectID, and/or dSnapshotDate, and returns a data.frame. See sample_fnFetchData() for an example. The returned data.frame contains information about the named domain. If the function throws an error, the error is elevated to the user, so you can use errors to pass requirements through to the user.

Value

A function that returns counts of rows in the specified domain data.

Examples

fnDataCounter <- ConstructDataCounter(sample_fnFetchData)
fnDataCounter("AE") == nrow(sample_fnFetchData("AE"))
#> [1] TRUE