Concatenation

Coral.Frame.concat stacks frames vertically. Pass frames with the same column names and types, in the same order, and a shared static row count. The result has the rows of each input in list order.

concat takes its output columns and order from the first frame. It does not validate the complete schema of every later frame: an additional column in a later frame is omitted. Check the schemas yourself before combining frames from different sources.

module Coral.BookConcat
import Coral.Frame (BoolCol, from_pairs, concat, nrows, int_col_of_list)
export (main)
def main() -> i64 = {
  lhs = from_pairs([("id", int_col_of_list([1i64, 2i64])), ("flag", BoolCol(to_tensor([true, false])))])
  rhs = from_pairs([("id", int_col_of_list([3i64, 4i64])), ("flag", BoolCol(to_tensor([true, true])))])
  nrows(concat([lhs, rhs]))
}

main returns 4. concat accepts IntCol, FloatCol, StringCol, and BoolCol; it carries integer missing-value masks through to the result. A different row count can be rejected because all inputs share the same Frame[n] type in this function's signature.