paleolimbot commented on a change in pull request #12751:
URL: https://github.com/apache/arrow/pull/12751#discussion_r839090211
##########
File path: r/R/record-batch.R
##########
@@ -189,3 +189,36 @@ record_batch <- RecordBatch$create
#' @export
names.RecordBatch <- function(x) x$names()
+
+#' @export
+rbind.RecordBatch <- function(...) {
+ stop("Use Table$create to combine record batches")
+}
+
+#' @export
+cbind.RecordBatch <- function(...) {
+ batches <- list(...)
+
+ # Assert they have the same length
+ unequal_length_idx <- which.min(lapply(batches, function(x) x$num_rows ==
batches[[1]]$num_rows))
+ if (unequal_length_idx != 1) {
+ stop(
+ sprintf(
+ "Cannot cbind batches with unequal number of rows. Batch 1 has %i,
batch %i has %i",
+ batches[[1]]$num_rows,
+ unequal_length_idx,
+ batches[[unequal_length_idx]]$num_rows
+ )
+ )
+ }
+
+ fields <- unlist(lapply(batches, function(tab) tab$schema$fields))
+ schema <- Schema$create(fields)
+ columns <- unlist(lapply(batches, function(tab) tab$columns))
+
+ # return new table
+ args <- columns
+ names(args) <- names(schema)
+ args$schema <- schema
+ do.call(RecordBatch$create, args)
Review comment:
You should be able to do `RecordBatch$create(!!! args, schema = schema)`
(because we use `rlang::list2()` to ingest `...`, which allows 'splicing' via
`!!!`).
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