Added str_to_sentence function. (#271)

* Added str_to_sentence function.

* Added bullet in NEWS.md

* Fixed line endings.

Author: jonthegeek

NAMESPACE

@@ -37,6 +37,7 @@ export(str_squish)
 export(str_sub)
 export(str_subset)
 export(str_to_lower)
+export(str_to_sentence)
 export(str_to_title)
 export(str_to_upper)
 export(str_trim)

NEWS.md

@@ -6,6 +6,9 @@
 * `str_subset()`, `str_detect()`, and `str_which()` gets `negate` argument,
   which is useful when you want the elements that do NOT match (#259,
   @yutannihilation).
+  
+* New `str_to_sentence()` function to capitalize with sentence case 
+  (@jonthegeek, #202)
 
 # stringr 1.3.1
 

R/case.R

@@ -8,6 +8,7 @@
 #' str_to_upper(dog)
 #' str_to_lower(dog)
 #' str_to_title(dog)
+#' str_to_sentence("the quick brown dog")
 #'
 #' # Locale matters!
 #' str_to_upper("i") # English
@@ -30,3 +31,11 @@ str_to_lower <- function(string, locale = "en") {
 str_to_title <- function(string, locale = "en") {
   stri_trans_totitle(string, opts_brkiter = stri_opts_brkiter(locale = locale))
 }
+#' @export
+#' @rdname case
+str_to_sentence <- function(string, locale = "en") {
+  stri_trans_totitle(
+    string,
+    opts_brkiter = stri_opts_brkiter(type = "sentence", locale = locale)
+  )
+}

man/case.Rd

@@ -10,3 +10,7 @@ test_that("to_upper and to_lower have equivalent base versions", {
 test_that("to_title creates one capital letter per word", {
   expect_equal(str_count(x, "\\W+"), str_count(str_to_title(x), "[[:upper:]]"))
 })
+
+test_that("to_sentence capitalizes just the first letter", {
+  expect_identical(str_to_sentence("a Test"), "A test")
+})