Dart CSV Writing

Question

Hey so I haven't really messed around with it too much, but I was wondering if there was actually a way (before I go down a neverending rabbit hole) to read and write to CSV files in Dart/Flutter? I need to write to the files, not necessarily read them, and I'm willing to go to quite extreme lengths to do so. Any library works, built-in functions are even better. Any and all help is appreciated!

Solution 1

Use package csv from https://pub.dartlang.org/packages/csv

If you have a List<List<dynamic>> items that needs to convert into csv,

String csv = const ListToCsvConverter().convert(yourListOfLists);

If you want to write the csv to a file,

/// Write to a file
final directory = await getApplicationDocumentsDirectory();
final pathOfTheFileToWrite = directory.path + "/myCsvFile.csv";
File file = await File(pathOfTheFileToWrite);
file.writeAsString(csv);    

Also, if you want to read a csv file directly into list<list<dynamic>>

final input = new File('a/csv/file.txt').openRead();
final fields = await input.transform(UTF8.decoder).transform(csvCodec.decoder).toList();

Solution 2

According to new packages and guidelines(2019) use following code

package csvfrom https://pub.dartlang.org/packages/csv.

If you have a List<List<dynamic>> items that needs to convert into csv,

String csv = const ListToCsvConverter().convert(yourListOfLists);

Then you can write the string to a file using file operations.

file.writeAsString('$csv');

Also, if you want to read a csv file directly into list<list<dynamic>>

final input = new File('a/csv/file.txt').openRead();
final fields = await input.transform(utf8.decoder).transform(new CsvToListConverter()).toList();

Comments

[Fethi]

when inserting to a CSV file, how to specify which file exactly?

[krishnakumarcn]

In the above example, the file is a/csv/file.txt. In an actual scenario, you can get your filepath from reading external storage directory or app directory. Use path_provider package for getting the directory path info. @Fethi

[Fethi]

but in the first code you mentioned when inserting you didn't specify any path, how does it insert to a it ?

[krishnakumarcn]

Updated the answer for the same @Fethi

[Michael Tolsma]

How would you append more data to the existing sheet? using mode: FileMode.append appends to the last entry without spaces or going to a new line, and doing "$csv\n" just gets overwritten by the next entry.