Add lines_to_matrix() (closes #4)

NAMESPACE

@@ -16,3 +16,4 @@ export(aoc_url_input)
 export(extract_numbers)
 export(gcd)
 export(lcm)
+export(lines_to_matrix)

NEWS.md

@@ -5,3 +5,4 @@
 * Add user agent to `aoc_get_input()`
 * Add `extract_numbers()` to extract all numbers from a string
 * Add `gcd()` and `lcm()` for finding greatest common divisor and lowest common multiple
+* Add `lines_to_matrix()`

R/read.R

@@ -117,7 +117,7 @@ aoc_input_matrix <- function(day, year = NULL, mode = c("character", "numeric"),
 
 	input <- readr::read_lines(aoc_input_path(day, year))
 
-	input <- matrix(unlist(strsplit(input, split = split)), nrow = length(input), byrow = TRUE)
+	input <- strsplit(input, split) |> do.call(rbind, args = _)
 
 	if (mode == "numeric") {
 		input <- apply(input, 2, as.numeric)

R/wrangle-helpers.R

@@ -0,0 +1,14 @@
+#' Convert vectors to a matrix
+#'
+#' For the default split of `"`, assumes that each element of `lines` has the same number of characters.
+#'
+#' @param lines a vector
+#' @param split character. The string to split the input on. Default is `""`, i.e. one character per column
+#'
+#' @return A matrix where the number of rows is the length of `lines` and, for a split on `"`, the number of columns is the same as the number of characters in each element of `lines`.
+#' @export
+#'
+#' @examples lines_to_matrix(c("#.#.", "..#.", "##.."))
+lines_to_matrix <- function(lines, split = "") {
+	strsplit(lines, split) |> do.call(rbind, args = _)
+}

_pkgdown.yml

@@ -33,6 +33,8 @@ reference:
     - aoc_input_data_frame
     - aoc_input_matrix
     - aoc_input_vector
+  - title: "Helpers for wrangling data"
+    - lines_to_matrix
   - title: "Helper functions for working with strings"
     contents:
     - extract_numbers

tests/testthat/test-wrangle-helpers.R

@@ -0,0 +1,8 @@
+# write test for lines_to_matrix
+test_that("lines_to_matrix works", {
+	expect_equal(lines_to_matrix(c("#.#.", "..#.", "##..")),
+							 matrix(c("#", ".", "#", ".",
+							 				 ".", ".", "#", ".",
+							 				 "#", "#", ".", "."
+							 				 ), byrow = TRUE, nrow = 3))
+})