CODEWITHSUNDEEP
dart
Nik Graf
Nik Graf

Reputation: 3739

How do get a random element from a List in Dart?

How can I retrieve a random element from a collection in Dart?

var list = ['a','b','c','d','e'];

Upvotes: 109

Views: 77352

Answers (9)

Yazan Alazab
Yazan Alazab

Reputation: 1

Also we can create CurrentStatu likes Whatsapp in following code

I used your answer , thx bro

import 'dart:math';
void main(){

var list = [0,1];

//TODO  generates a new Random object with for()
final _random = new Random();
var element = list[_random.nextInt(list.length)];

Status Statuscurrent = Status.values.elementAt(element);
print(Statuscurrent);
}

enum Status{ 
online,
offline
}

Upvotes: 0

Reinier Garcia
Reinier Garcia

Reputation: 1770

import 'dart:math';

final _random = Random();

// from MIN(inclusive), to MAX(inclusive).
int randomBetweenIncInc(int min, int max) => min + _random.nextInt((max + 1) - min);

var list = ['a','b','c','d','e'];
var element = list[randomBetweenIncInc(0, list.length - 1)];

Upvotes: 2

Chuck Batson
Chuck Batson

Reputation: 2774

This is provided by the collection package's IterableExtension.sample() method:

import 'package:collection/collection.dart';
var list = ['a','b','c','d','e'];
print(list.sample(1).single);

Example output:

e

Note that the method is generalized to return N samples of the list.

Upvotes: 8

DiyorbekDev
DiyorbekDev

Reputation: 774

var list = ['a','b','c','d','e'];
list.elementAt(Random().nextInt(list.length));

Upvotes: 7

763
763

Reputation: 1693

I just created an extension method for List.

import 'dart:math';

extension RandomListItem<T> on List<T> {
  T randomItem() {
    return this[Random().nextInt(length)];
  }
}

We can use it like this.

List.randomItem()

example :

Scaffold(
      body: SafeArea(
        child: isItLogin
            ? Lottie.asset('assets/lottie/53888-login-icon.json')
            : Lottie.asset(LottieAssets.loadingAssets.randomItem()),
      ),
    );

Upvotes: 17

Razi Kallayi
Razi Kallayi

Reputation: 900

import "dart:math";

var list = ['a','b','c','d','e'];

list[Random().nextInt(list.length)]

Upvotes: 31

Jerome Puttemans
Jerome Puttemans

Reputation: 1113

This works too:

var list = ['a','b','c','d','e'];

//this actually changes the order of all of the elements in the list 
//randomly, then returns the first element of the new list
var randomItem = (list..shuffle()).first;

or if you don't want to mess the list, create a copy:

var randomItem = (list.toList()..shuffle()).first;

Upvotes: 99

Kirollos Morkos
Kirollos Morkos

Reputation: 2711

You can use the dart_random_choice package to help you.

import 'package:dart_random_choice/dart_random_choice.dart';

var list = ['a','b','c','d','e'];
var el = randomChoice(list);

Upvotes: 11

Nik Graf
Nik Graf

Reputation: 3739

import "dart:math";

var list = ['a','b','c','d','e'];

// generates a new Random object
final _random = new Random();

// generate a random index based on the list length
// and use it to retrieve the element
var element = list[_random.nextInt(list.length)];

Upvotes: 180

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