Documented Standard Error code

NAMESPACE

@@ -12,12 +12,15 @@ export(get_row)
 export(if_else_)
 export(is_invalid)
 export(residuals_PRESS)
+export(se)
 export(set_colnames)
 export(set_rownames)
 export(vif_lm)
 importFrom(car,vif)
 importFrom(dplyr,"%>%")
+importFrom(dplyr,first)
 importFrom(dplyr,nth)
+importFrom(purrr,"%@%")
 importFrom(purrr,discard)
 importFrom(purrr,map)
 importFrom(purrr,map_chr)
@@ -26,4 +29,5 @@ importFrom(purrr,map_int)
 importFrom(purrr,transpose)
 importFrom(stats,lm)
 importFrom(stats,lm.influence)
+importFrom(stats,predict)
 importFrom(stats,residuals)

R/model_functions.R

@@ -1,4 +1,27 @@
 
+#' Standard Errors
+#'
+#' Returns the standard errors of the fit againt the data.
+#' (y - yhat)^2
+#' Without a supplied dataframe, returns the errors from the training fit
+#'
+#' @param fit Object of class "lm". A fitted model.
+#' @param df DataFrame of predictors and predicted (optional)
+#' @return double Squared differences of predicted and actual values
+#' @examples
+#' data.frame(y=1:5,x=c(1,2,2,4,5)) -> df1
+#' data.frame(y=3:7,x=c(3,4,6,5,2)) -> df2
+#' lm(y ~ ., df1) -> fit
+#'
+#' se(fit,df1)
+#' se(fit,df2)
+#' se(fit)
+#'
+#' @export
+#' @importFrom dplyr %>%
+#' @importFrom dplyr first
+#' @importFrom purrr %@%
+#' @importFrom stats predict
 se <- function(fit, df = NULL) {
   if (is.null(df)) {
     # without a supplied to predict the fit, just use the attached values
@@ -9,12 +32,14 @@ se <- function(fit, df = NULL) {
     return(simple_se)
   }
 
+  # the first element of the terms is the regressor
   fit %>%
     get_("terms") %@%
     "factors" %>%
     rownames %>%
     first -> regressor
 
+  # return the squared difference between predicted and actual value
   fit %>%
     predict(df) %>%
     `-`(df[[regressor]]) %>%