ARROW-12967: [R] Add bindings for pmin() and pmax()

r/R/dplyr-functions.R

@@ -398,6 +398,22 @@ nse_funcs$str_split <- function(string, pattern, n = Inf, simplify = FALSE) {
   )
 }
 
+nse_funcs$pmin <- function(..., na.rm = FALSE) {
+  build_expr(
+    "min_element_wise",
+    ...,
+    options = list(skip_nulls = na.rm)
+  )
+}
+
+nse_funcs$pmax <- function(..., na.rm = FALSE) {
+  build_expr(
+    "max_element_wise",
+    ...,
+    options = list(skip_nulls = na.rm)
+  )
+}
+
 # String function helpers
 
 # format `pattern` as needed for case insensitivity and literal matching by RE2
@@ -511,24 +527,24 @@ nse_funcs$second <- function(x) {
 }
 
 # After ARROW-13054 is completed, we can refactor this for simplicity
-# 
+#
 # Arrow's `day_of_week` kernel counts from 0 (Monday) to 6 (Sunday), whereas
 # `lubridate::wday` counts from 1 to 7, and allows users to specify which day
 # of the week is first (Sunday by default).  This Expression converts the returned
 # day of the week back to the value that would be returned by lubridate by
 # providing offset values based on the specified week_start day, and adding 1
 # so the returned value is 1-indexed instead of 0-indexed.
 nse_funcs$wday <- function(x, label = FALSE, abbr = TRUE, week_start = getOption("lubridate.week.start", 7)) {
-  
+
   # The "day_of_week" compute function returns numeric days of week and not locale-aware strftime
   # When the ticket below is resolved, we should be able to support the label argument
   # https://issues.apache.org/jira/browse/ARROW-13133
   if (label) {
     arrow_not_supported("Label argument")
   }
-  
+
   # overall formula to convert from arrow::wday to lubridate::wday is:
   #  ((wday(day) - start + 8) %% 7) + 1
   ((Expression$create("day_of_week", x) - Expression$scalar(week_start) + 8) %% 7) + 1
-  
+
 }

r/src/compute.cpp

@@ -180,6 +180,15 @@ std::shared_ptr<arrow::compute::FunctionOptions> make_compute_options(
     return out;
   }
 
+  if (func_name == "min_element_wise" || func_name == "max_element_wise") {
+    using Options = arrow::compute::ElementWiseAggregateOptions;
+    bool skip_nulls = true;
+    if (!Rf_isNull(options["skip_nulls"])) {
+      skip_nulls = cpp11::as_cpp<bool>(options["skip_nulls"]);
+    }
+    return std::make_shared<Options>(skip_nulls);
+  }
+
   if (func_name == "quantile") {
     using Options = arrow::compute::QuantileOptions;
     auto out = std::make_shared<Options>(Options::Defaults());

r/tests/testthat/test-dplyr-mutate.R

@@ -418,3 +418,34 @@ test_that("mutate and write_dataset", {
       summarize(mean = mean(integer))
   )
 })
+
+test_that("mutate and pmin/pmax", {
+  df <- tibble(
+    city = c("Chillan", "Valdivia", "Osorno"),
+    val1 = c(200, 300, NA),
+    val2 = c(100, NA, NA),
+    val3 = c(0, NA, NA)
+  )
+
+  expect_dplyr_equal(
+    input %>%
+      mutate(
+        max_val_1 = pmax(val1, val2, val3),
+        max_val_2 = pmax(val1, val2, val3, na.rm = T),
+        min_val_1 = pmin(val1, val2, val3),
+        min_val_2 = pmin(val1, val2, val3, na.rm = T)
+      ) %>%
+      collect(),
+    df
+  )
+
+  expect_dplyr_equal(
+    input %>%
+      mutate(
+        max_val_1 = pmax(val1 - 100, 200, val1 * 100, na.rm = T),
+        min_val_1 = pmin(val1 - 100, 100, val1 * 100, na.rm = T),
+      ) %>%
+      collect(),
+    df
+  )
+})