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Row

info

This page is aligned to Apache Arrow JS v21.x (apache-arrow).

A Row is the row-level object returned by nested Struct vectors and by Table/RecordBatch row access. Rows behave like read-only tuples keyed by index and field name.

Usage​

import {makeVector, Struct, Field, Int32, Utf8} from 'apache-arrow';

const rows = makeVector(
  [
    {id: 1, value: 'foo'},
    {id: 2, value: 'bar'}
  ],
  new Struct([new Field('id', new Int32()), new Field('value', new Utf8())])
);

const row = rows.get(0);
console.log(row?.[0], row?.id, row?.value);
import {makeVector, Struct, Field, Utf8, Int32} from 'apache-arrow';

const names = makeVector(
  [
    {id: 1, name: 'Alice'},
    {id: 2, name: 'Bob'}
  ],
  new Struct([new Field('id', new Int32()), new Field('name', new Utf8())])
);

for (const row of names) {
  console.log(row.id, row.size, row.toString());
}

StructRow API​

Methods​

  • toArray(): T[string]["TValue"][] — Materializes row fields to a plain array.
  • toJSON(): { [P in string & keyof T]: T[P]["TValue"]; } — Returns row values as a JSON object.
  • toString(): string — Returns a debug string.
  • [Symbol.iterator](): IterableIterator<[keyof T, T[keyof T]['TValue'] | null]> — Iterates [key, value] entries.
  • size: number — Number of fields in the row.

Rows can also be used directly in for...of, bracket access, and property-style access.