thisisnic commented on a change in pull request #10100:
URL: https://github.com/apache/arrow/pull/10100#discussion_r617659788
##########
File path: cpp/src/arrow/record_batch.cc
##########
@@ -253,6 +253,27 @@ bool RecordBatch::ApproxEquals(const RecordBatch& other)
const {
return true;
}
+Result<std::shared_ptr<RecordBatch>> RecordBatch::SelectColumns(
+ const std::vector<int>& indices) const {
+ int n = static_cast<int>(indices.size());
+
+ std::vector<std::shared_ptr<Field>> fields(n);
+ std::vector<std::shared_ptr<Array>> columns(n);
+
+ for (int i = 0; i < n; i++) {
+ int pos = indices[i];
+ if (pos < 0 || pos > num_columns() - 1) {
+ return Status::Invalid("Invalid column index ", pos, " to select
columns.");
+ }
+ fields[i] = schema()->field(pos);
+ columns[i] = column(pos);
+ }
+
+ auto new_schema =
+ std::make_shared<arrow::Schema>(std::move(fields), schema()->metadata());
+ return RecordBatch::Make(new_schema, num_rows(), columns);
Review comment:
Thanks - will try to make both of these changes as I'm new to C++ so
useful for me to learn!
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