feat: Add near()

Closes #36
nathaneastwood · Jun 7, 2020 · 44579f6 · 44579f6
1 parent fb07dd5
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diff --git a/DESCRIPTION b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: poorman
 Type: Package
 Title: A Poor Man's Base R Copy of 'dplyr' Verbs
-Version: 0.2.0.19
+Version: 0.2.0.20
 Authors@R: person("Nathan", "Eastwood", "", "[email protected]",
     role = c("aut", "cre"))
 Maintainer: Nathan Eastwood <[email protected]>

diff --git a/NAMESPACE b/NAMESPACE
@@ -60,6 +60,7 @@ export(min_rank)
 export(mutate)
 export(n)
 export(n_distinct)
+export(near)
 export(ntile)
 export(num_range)
 export(peek_vars)

diff --git a/R/near.R b/R/near.R
@@ -0,0 +1,16 @@
+#' Compare two numeric vectors
+#'
+#' This is a safe way of comparing if two vectors of floating point numbers are (pairwise) equal.  This is safer than
+#' using `==`, because it has a built in tolerance.
+#'
+#' @param x,y Numeric vectors to compare
+#' @param tol Tolerance of comparison.
+#'
+#' @examples
+#' sqrt(2) ^ 2 == 2
+#' near(sqrt(2) ^ 2, 2)
+#'
+#' @export
+near <- function(x, y, tol = .Machine$double.eps^0.5) {
+  abs(x - y) < tol
+}
diff --git a/inst/tinytest/test_near.R b/inst/tinytest/test_near.R
@@ -0,0 +1,4 @@
+expect_true(
+  near(sqrt(2)^2, 2),
+  info = "near() accepts nearby fp values"
+)
diff --git a/man/near.Rd b/man/near.Rd