thisisnic commented on a change in pull request #12083:
URL: https://github.com/apache/arrow/pull/12083#discussion_r785474474
##########
File path: r/R/dataset.R
##########
@@ -123,6 +123,7 @@
#' or call [`$NewScan()`][Scanner] to construct a query directly.
#' @export
#' @seealso `vignette("dataset", package = "arrow")`
+#' See [read_csv_arrow()] on how to specify column names and types for
"csv"/"text" and "tsv" -formats.
Review comment:
This is great, though I think it might fit better after the content on
line 121 along with links to `read_feather()` and `read_parquet()` and a more
generic comment about viewing those page for format-specific options.
##########
File path: r/R/dataset-format.R
##########
@@ -122,6 +122,18 @@ CsvFileFormat$create <- function(...,
opts = csv_file_format_parse_options(...),
convert_options =
csv_file_format_convert_opts(...),
read_options =
csv_file_format_read_opts(...)) {
+
+ options <- list(...)
+ schema <- options[["schema"]]
+
+ if (length(read_options$column_names) > 0 & !is.null(schema) &
!identical(names(schema), read_options$column_names)) {
+ abort(c(
+ '"column_names" in read_options do not match the schema.',
+ i = "Set column_names in read_options to match the schema",
+ i = "Omit the read_options argument"
+ ))
Review comment:
Looking good, just a couple of suggestions:
- the user of the `open_dataset()` function won't necessarily have used the
function `read_options()` directly, so we should remove the reference to it to
avoid confusion
- to provide maximal useful information to the end-user, could you print out
the arguments which are mismatches between `column_names` and the schema?
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