From e645d00fca3fcaeb6bd2f60d9781eaf8609e5eb8 Mon Sep 17 00:00:00 2001
From: Waldir Leoncio <waldir.leoncio@gmail.com>
Date: Thu, 30 Jan 2020 15:44:13 +0100
Subject: [PATCH] Implemented base MATLAB function in R

---
 R/size.R                                     | 30 ++++++++++++++++++++
 man/size.Rd                                  | 23 +++++++++++++++
 tests/testthat/test-convertedBaseFunctions.R | 19 +++++++++++++
 3 files changed, 72 insertions(+)
 create mode 100644 R/size.R
 create mode 100644 man/size.Rd

diff --git a/R/size.R b/R/size.R
new file mode 100644
index 0000000..ce245f7
--- /dev/null
+++ b/R/size.R
@@ -0,0 +1,30 @@
+#' @title Size of an object
+#' @description This functions tries to replicate the behavior of the base function "size" in Matlab
+#' @param x object to be evaluated
+#' @param d dimension of object to be evaluated
+#' @note On MATLAB, size(1, 100) returns 1. As a matter of fact, if the user 
+#' calls for a dimension which x doesn't have `size()` always returns 1. R's
+#' default behavior is more reasonable in those cases (i.e., returning NA),
+#' but since the point of this function is to replicate MATLAB behaviors
+#' (bugs and questionable behaviors included), this function also does this.
+size <- function(x, d) {
+    # Determining the number of dimensions
+    if (length(x) == 1) {
+        # x is surely a scalar
+        return(1)
+    } else {
+        # x is a vector, a matrix or an array
+        n_dim <- ifelse(is.null(dim(x)), 1, length(dim(x)))
+        if (missing(d)) {
+            if (n_dim == 1) {
+                out <- range(x)
+            } else {
+                out <- dim(x)
+            }
+        } else {
+            out <- ifelse(n_dim == 1, range(x)[d], dim(x)[d])
+            if (is.na(out)) out <- 1  # for MATLAB compatibility
+        }
+        return(out)
+    }
+}
\ No newline at end of file
diff --git a/man/size.Rd b/man/size.Rd
new file mode 100644
index 0000000..5c2c3cb
--- /dev/null
+++ b/man/size.Rd
@@ -0,0 +1,23 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/size.R
+\name{size}
+\alias{size}
+\title{Size of an object}
+\usage{
+size(x, d)
+}
+\arguments{
+\item{x}{object to be evaluated}
+
+\item{d}{dimension of object to be evaluated}
+}
+\description{
+This functions tries to replicate the behavior of the base function "size" in Matlab
+}
+\note{
+On MATLAB, size(1, 100) returns 1. As a matter of fact, if the user 
+calls for a dimension which x doesn't have `size()` always returns 1. R's
+default behavior is more reasonable in those cases (i.e., returning NA),
+but since the point of this function is to replicate MATLAB behaviors
+(bugs and questionable behaviors included), this function also does this.
+}
diff --git a/tests/testthat/test-convertedBaseFunctions.R b/tests/testthat/test-convertedBaseFunctions.R
index 9a9c9c4..f4bf346 100644
--- a/tests/testthat/test-convertedBaseFunctions.R
+++ b/tests/testthat/test-convertedBaseFunctions.R
@@ -65,4 +65,23 @@ test_that("times works as expected", {
 test_that("colon works as expected (hee hee)", {
     expect_equal(colon(1, 4), 1:4)
     expect_length(colon(4, 1), 0)
+})
+
+test_that("size works as on MATLAB", {
+    sk <- 10
+    vk <- 1:4
+    mx <- matrix(1:6, 2)
+    ra <- array(1:24, c(2, 3, 4))
+    expect_equal(size(sk), 1)
+    expect_equal(size(vk), c(1, 4))
+    expect_equal(size(mx), c(2, 3))
+    expect_equal(size(ra), c(2, 3, 4))
+    expect_equal(size(sk, 199), 1)
+    expect_equal(size(vk, 199), 1)
+    expect_equal(size(mx, 199), 1)
+    expect_equal(size(ra, 199), 1)
+    expect_equal(size(vk, 2), 4)
+    expect_equal(size(mx, 2), 3)
+    expect_equal(size(ra, 2), 3)
+    expect_equal(size(ra, 3), 4)
 })
\ No newline at end of file