R/drop-rows.R

In crunch: Crunch.io Data Tools

#' Permanently delete rows from a dataset
#'
#' @param dataset a `CrunchDataset`
#' @param expr a `CrunchLogicalExpr`
#' @return `dataset` without the rows indicated by `expr`
#' @seealso [exclusion] for a non-destructive way to suppress rows
#' @examples
#' \dontrun{
#' ds <- dropRows(ds, ds$gender == "Male")
#' }
#' @export
dropRows <- function(dataset, expr) {
    if (!length(expr)) {
        ## Could be NULL or like NULL == something, which is logical(0)
        halt("Invalid expression: ", deparseAndFlatten(match.call()$expr))
    }
    payload <- list(command = "delete", filter = zcl(expr))
    crPOST(shojiURL(dataset, "fragments", "table"), body = toJSON(payload))
    dropCache(self(dataset)) ## Could do a more surgical cache drop, but this is safe
    return(dataset)
}