nealrichardson commented on a change in pull request #11143: URL: https://github.com/apache/arrow/pull/11143#discussion_r709206829
########## File path: r/R/dplyr-distinct.R ########## @@ -0,0 +1,63 @@ +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. + +# The following S3 methods are registered on load if dplyr is present + +distinct.arrow_dplyr_query <- function(.data, ..., .keep_all = FALSE) { + if (.keep_all == TRUE) { + # After ARROW-13993 is merged, we can implement this + arrow_not_supported("`distinct()` with `.keep_all = TRUE`") + } + + distinct_groups <- ensure_named_exprs(quos(...)) Review comment: I'd expect a function body something like this: ``` .data <- dplyr::group_by(.data, ..., .add = TRUE) gv <- dplyr::group_vars(.data) # this is `names(.data$group_by_vars)` if (length(gv)) { # `data %>% group_by() %>% summarise()` returns cols in order supplied # but distinct() returns cols in dataset order, so sort group vars vars_in_data <- names(.data)[names(.data) %in% gv] .data$group_by_vars <- c( .data$group_by_vars[vars_in_data], .data$group_by_vars[!(gv %in% vars_in_data)] ) } else { # distinct() with no vars specified means distinct across all cols .data <- dplyr::group_by(.data, !!!syms(names(.data))) } # TODO: use .groups = "keep" (ARROW-13550) dplyr::summarize(.data) ``` IIUC the only specialness about distinct() over group_by() %>% summarize() is the order of columns and the meaning of 0 groups. If that's true then we should delegate the rest of the work to group_by and summarize. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
