Added isfield translation function

R/isfield.R

@@ -0,0 +1,9 @@
+#' @title Checks if a list contains a field
+#' @description This function tries to replicate the behavior of the `isfield`
+#' function in Matlab
+#' @param x list
+#' @param field name of field
+#' @references https://se.mathworks.com/help/matlab/ref/isfield.html
+isfield <- function(x, field) {
+    field %in% names(x)
+}