add this_in_that

Author: mkearney

NAMESPACE

@@ -90,6 +90,7 @@ export(show_connections)
 export(substrev)
 export(theme_mwk)
 export(theme_mwk_caption_text)
+export(this_in_that)
 export(trim_ws)
 export(un_zip)
 export(write_function)

R/this_in_that.R

@@ -0,0 +1,19 @@
+#' Where is this in that?
+#'
+#' Looks up (matches) the position of \code{this} in \code{that} (table)
+#'
+#' @param this Values to look up in that
+#' @param that Value positions matched to this
+#' @param value Optional, values to be returned rather than the default, which
+#'   returns positions (integers)
+#' @export
+this_in_that <- function(this, that, value = NULL) {
+  m <- match(this, that)
+  if (is.null(value)) {
+    return(m)
+  }
+  if (length(that) != length(value)) {
+    stop("'value' must be same length as 'that' (table)", call. = FALSE)
+  }
+  value[m]
+}