nealrichardson commented on a change in pull request #10191:
URL: https://github.com/apache/arrow/pull/10191#discussion_r628427550
##########
File path: r/R/dplyr.R
##########
@@ -58,40 +63,36 @@ arrow_dplyr_query <- function(.data) {
)
}
+make_field_refs <- function(field_names) {
+ set_names(lapply(field_names, Expression$field_ref), field_names)
+}
+
#' @export
print.arrow_dplyr_query <- function(x, ...) {
schm <- x$.data$schema
- cols <- get_field_names(x)
- # If cols are expressions, they won't be in the schema and will be "" in cols
- fields <- map_chr(cols, function(name) {
+ fields <- map_chr(x$selected_columns, function(expr) {
+ name <- expr$field_name
if (nzchar(name)) {
schm$GetFieldByName(name)$ToString()
} else {
+ # It's "" because this is not a field_ref, it's a more complex expression
"expr"
Review comment:
Cool, I hadn't thought about printing the expression, that seems
doable/already done on the R side. But how do I find out the type that the
expression will yield?
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