toColumnar function

Map<String, List<Object?>> toColumnar(
  1. List<Map<String, Object?>> rows
)

Returns map of key -> list of values for all keys in rows.

Implementation

Map<String, List<Object?>> toColumnar(List<Map<String, Object?>> rows) {
  if (rows.isEmpty) return <String, List<Object?>>{};
  final Map<String, List<Object?>> out = <String, List<Object?>>{};
  final firstRow = rows.firstOrNull;
  if (firstRow == null) return out;
  for (final String k in firstRow.keys) {
    out[k] = columnValues(rows, k);
  }
  return out;
}