How do I create a CSV file in Dart?

Call encode on a CsvCodec with your rows to get CSV text, then write it with CsvFile.write. Use CsvCodec.excel() if the file will be opened in Excel.

How to write CSV in Dart

Encode rows to CSV text, with quoting handled so the output survives a round trip.

Install#

dart pub add csv_plus

import 'package:csv_plus/csv_plus.dart';

Encode rows#

final codec = CsvCodec();

final csv = codec.encode([
  ['name', 'age', 'score'],
  ['Alice', 30, 95.5],
  ['Bob', 25, 88.0],
]);

Fields that need quoting get quoted. A value containing the delimiter, a quote character or a line break is wrapped and escaped for you, so the result reads back as the same data.

Quoting#

// Quote every field, not just the ones that need it.
final always = CsvCodec(CsvConfig(quoteMode: QuoteMode.always));

Writing for Excel#

Excel is particular. It expects a semicolon delimiter in many locales, and without a UTF-8 BOM it mangles non-ASCII text. There is a preset:

final excel = CsvCodec.excel(); // ';' delimiter plus a UTF-8 BOM

Writing to a file#

import 'package:csv_plus/io.dart';

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

Two-column CSV from a map#

codec.encodeMap({'host': 'localhost', 'port': 8080});
// host,localhost
// port,8080