Check if Logical Conditions Hold for a Specific Data Row

Designed as a helper function for check_that(), this function checks whether user-supplied logical conditions hold true for a specific data row.

Usage

for_case(case, ...)

Arguments

case: A row number or a logical vector identifying the specific data row(s) to check. If a logical vector, it must have exactly 1 TRUE element (i.e., that can be used to infer the row of interest).
...: A set of logical conditions to be checked.

Value

A logical value indicating whether ALL specified conditions hold true for the specified data row (i.e., case).

Details

This function is useful for checking if certain logical conditions are met for a specific data row in your dataset. You can provide one or more logical conditions as arguments, and the function will evaluate them for the specified row.

If you provide a row number (case), the function will check the conditions for that specific row. If case is a logical vector, it will check the conditions for rows where case is TRUE. Note, when case is a logical vector, it must have exactly one TRUE element that can then be used to infer the row of interest. Internally, this is done with a call to which().

If the specified case is not a valid count (i.e., a row number) or does not satisfy the condition length(which(case)) == 1, the function will throw an error.

Examples

# for_case is designed primarily as a helper function for check_that
sample_data <- data.frame(id = c(11, 22, 33), group = c("A", "B", "C"))

sample_data |>
  check_that(
    for_case(2, group == "B"), # case given as number
    for_case(id == 22, group == "B") # case given as logical vector
  )
#> ✔ all data checks passing

# for_case will technically work with simple vectors too
backwards_letters <- rev(letters)
for_case(3, backwards_letters == "x") # TRUE
#> [1] TRUE