How to read a CSV file in Dart

Load a file from disk into rows you can work with.

Install#

dart pub add csv_plus

import 'package:csv_plus/csv_plus.dart';

Read a file#

File helpers live in a separate import, so the core library never pulls in dart:io and still works in the browser.

import 'package:csv_plus/io.dart';

void main() async {
  final table = await CsvFile.read('data.csv');

  print(table.rows.length);
  print(table.rows.first['name']);
}

Write and append#

await CsvFile.write('out.csv', table);
await CsvFile.append('out.csv', [['Zoe', 41]]);

Reading a file you already hold as text#

If the content arrived over the network or from an asset rather than disk, decode it directly and skip the io import:

import 'package:csv_plus/csv_plus.dart';

final rows = CsvCodec().decode(responseBody);

Large files#

Reading a whole file into memory is fine until it is not. For anything big, stream it instead, which holds one row at a time regardless of file size:

import 'package:csv_plus/io.dart';

await for (final row in CsvFile.stream('huge.csv')) {
  process(row);
}

See large files for the detail, including byte streams and backpressure.