Print list object flutter

This tutorial shows you how to join a List to a String with any separator in Dart/Flutter.

Using String join[]

Dart's List class has an instance method join[] that can be used to join a List of any type to a String.

String join[[String separator = ""]]

Below is a simple example in which we are going to join a list of strings into a string. Without passing the separator parameter, the default separator [empty string] will be used. Therefore, the result is the same as concatenating the values without a separator.

List values = ['dart', 'flutter', 'programming']; print[values.join[]];

Output:

dartflutterprogramming

If you pass an argument, it will be used as the separator between elements.

List values = ['dart', 'flutter', 'programming']; print[values.join[',']];

Output:

dart,flutter,programming

In case you want to transform the value first, you can create a chain and map the values first before adding join at the end of the chain.

List values = [' dart', 'flutter ', 'programming']; String result = values .map[[val] => val.trim[]] .join[',']; print[result];

Output:

dart,flutter,programming

Join Object

How to handle If the list is a collection of objects, not simple data types [such as string, double, or int? Dart uses toString method of the object's class. Therefore, if you create your own class and you want to join a list of the object into a string, it is necessary to override toString method.

class Item { int id; String name; Item[{this.id, this.name}]; @override String toString[] { return '{id: $id, name: $name}'; } } Item item1 = Item[id: 1, name: 'Item One']; Item item2 = Item[id: 2, name: 'Item Two']; Item item3 = Item[id: 3, name: 'Item Three']; List items = [item1, item2, item3]; print[items.join[',']];

Output:

{id: 1, name: Item One},{id: 2, name: Item Two},{id: 3, name: Item Three}

Without overriding toString, the output will be:

Instance of 'Item',Instance of 'Item',Instance of 'Item'

That's all about how to convert a List into a String with separator. If you want to perform the reverse thing, you can read our tutorial about how to convert a List with any delimiter to a String.