Added function.

NAMESPACE

@@ -56,6 +56,7 @@ export(any_na)
 export(as_discrete)
 export(as_factor)
 export(bin)
+export(cheapr_var)
 export(col_all_na)
 export(col_any_na)
 export(col_na_counts)

R/extras.R

@@ -20,6 +20,8 @@
 #' randomly into your vector.
 #' @param prop Proportion of scalar values (or `NA`) values to insert
 #' randomly into your vector.
+#' @param na.rm Should `NA` values be ignored in `cheapr_var()` Default is
+#' `TRUE`.
 #'
 #' @returns
 #' `enframe()_` converts a vector to a data frame. \cr
@@ -40,14 +42,8 @@
 #' Useful for generating missing data. \cr
 #' `vector_length` behaves mostly like `NROW()` except
 #' for matrices in which it matches `length()`.
-#'
-#' @details
-#' `intersect_()` and `setdiff_()` are faster and more efficient
-#' alternatives to `intersect()` and `setdiff()` respectively. \cr
-#' `enframe_()` and `deframe_()` are faster alternatives to
-#' `tibble::enframe()` and `tibble::deframe()` respectively. \cr
-#' `cut_numeric()` is a faster and more efficient alternative to
-#' `cut.default()`.
+#' `cheapr_var` returns the variance of a numeric vector.
+#' No coercion happens for integer vectors and so is very cheap.
 #'
 #' @export
 #' @rdname extras
@@ -206,6 +202,34 @@ na_insert <- function(x, n = NULL, prop = NULL){
 #' @export
 #' @rdname extras
 vector_length <- cpp_vec_length
+#' @export
+#' @rdname extras
+cheapr_var <- function(x, na.rm = TRUE){
+  if (is.integer(x)){
+    y <- as.integer(x)
+  } else {
+    y <- as.double(x)
+  }
+  if (na.rm){
+    N <- (length(y) - na_count(y)) - 1
+  } else {
+    N <- length(y) - 1
+  }
+  if (N < 1){
+    return(NA_real_)
+  } else {
+    mu <- collapse::fmean(y, na.rm = na.rm)
+    if (is.na(mu)){
+      NA_real_
+    } else {
+      var_sum_squared_diff(y, as.double(mu)) /  N
+    }
+  }
+}
+cheapr_sd <- function(x, na.rm = TRUE){
+  sqrt(cheapr_var(x, na.rm = na.rm))
+}
+
 
 # head_ <- function(x, n = 1L){
 #   check_length(n, 1L)

R/utils.R

@@ -148,26 +148,3 @@ n_dots <- function(...){
 
 # Keep this in-case anyone was using it
 fill_with_na <- na_insert
-
-# Basically if x is integer no vector conversion to double happens
-cheapr_var <- function(x, na.rm = TRUE){
-  if (is.integer(x)){
-    y <- as.integer(x)
-  } else {
-    y <- as.double(x)
-  }
-  if (na.rm){
-    N <- (length(y) - na_count(y)) - 1
-  } else {
-    N <- length(y) - 1
-  }
-  mu <- collapse::fmean(y, na.rm = na.rm)
-  if (length(mu) < 1 || any_na(mu)){
-    NA_real_
-  } else {
-    var_sum_squared_diff(y, as.double(mu)) /  N
-  }
-}
-cheapr_sd <- function(x, na.rm = TRUE){
-  sqrt(cheapr_var(x, na.rm = na.rm))
-}

cran-comments.md

@@ -1,4 +1,4 @@
-* Updated to version 0.9.8
+* Updated to version 0.9.9
 
 * Checked and passed using rhub v2.0.0 in the following environments: