jonkeane commented on a change in pull request #10780: URL: https://github.com/apache/arrow/pull/10780#discussion_r675735126
########## File path: r/R/duckdb.R ########## @@ -0,0 +1,115 @@ +# 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. + +#' Create a (virtual) DuckDB table from an Arrow object +#' +#' This will do the necessary configuration to create a (virtual) table in DuckDB +#' that is backed by the Arrow object given. No data is copied or modified until +#' `collect()` or `compute()` are called or a query is run against the table. +#' +#' The result is a dbplyr-compatible object that can be used in d(b)plyr pipelines. +#' +#' Alternatively, one can pass the argument `.engine = "duckdb"` to `summarise()` +#' that starts with an Arrow object to use DuckDB to calculate the summarization +#' step. Internally, this calls `to_duckdb()` with all of the default argument +#' values. +#' +#' @param src the Arrow object (e.g. Dataset, Table) to use for the DuckDB table +#' @param con a DuckDB connection to use (default will create one and store it +#' in `options("arrow_duck_con")`) +#' @param table_name a name to use in DuckDB for this object. The default is a +#' unique string `"arrow_"` followed by numbers. +#' @param auto_disconnect should the table be automatically cleaned up when the +#' resulting object is removed (and garbage collected)? Default: `TRUE` +#' +#' @return A `tbl` of the new table in DuckDB +#' +#' @name to_duckdb +#' @export +#' @examplesIf arrow_with_dataset() && requireNamespace("duckdb", quietly = TRUE) && requireNamespace("dplyr", quietly = TRUE) +#' library(dplyr) +#' +#' ds <- InMemoryDataset$create(mtcars) +#' +#' ds %>% +#' filter(mpg < 30) %>% +#' to_duckdb() %>% +#' group_by(cyl) %>% +#' summarize(mean_mpg = mean(mpg, na.rm = TRUE)) +#' +#' # the same query can be simplified using .engine = "duckdb" +#' ds %>% +#' filter(mpg < 30) %>% +#' group_by(cyl) %>% +#' summarize(mean_mpg = mean(mpg, na.rm = TRUE), .engine = "duckdb") +#' +to_duckdb <- function( + src, + con = arrow_duck_connection(), + table_name = unique_arrow_tablename(), + auto_disconnect = TRUE) { + duckdb::duckdb_register_arrow(con, table_name, src) + + tbl <- tbl(con, table_name) + groups <- src$group + if (length(groups) > 0 && !is.null(groups)) { + tbl <- dplyr::group_by(tbl, !!rlang::sym(groups)) + } Review comment: 👍 -- 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]
