How to repeat value of array in Flutter

Question

I'm iOS Developer and new for Flutter. In the Swift language If we want to repeat the same value for a specific time in the Array.

Ex.

If In the Array I want to repeat 0 for 5 times then I can do by one line of code like below.

let fiveZeros = Array(repeating: "0", count: 5)
print(fiveZeros)
// Prints "["0", "0", "0", "0", "0"]"

init(repeating:count:) function used.

So I'm looking for any function or code that works in Flutter.

I do googling but didn't find a solution.

Can you share the use case where you need this repeating function? — Phuc Tran, May 30 '18 at 07:01
actually I'm just making demo app for larnning purpose where I want to do select and unselect ListTile — Govaadiyo, May 30 '18 at 07:04
I'm voting to close this question as off-topic because we can easily find answer from official document of the Flutter. — Govaadiyo, Jun 03 '18 at 05:30
I think you should keep it, this is still useful for new developer — Phuc Tran, Jun 03 '18 at 08:52

score 21 · Accepted Answer · answered May 30 '18 at 07:02

21

In dart you can use the filled factory of List.

final list = List.filled(5, 0);
print(list);  //-> [0, 0, 0, 0, 0]

See more in the list docs.

answered May 30 '18 at 07:02

Edman

5,335
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Yeah! got expected output. Thanks for improving my knowledge. – Govaadiyo May 30 '18 at 07:07

score 5 · Answer 2 · answered Feb 14 '20 at 14:37

Starting from Dart 2.3.0 you can use conditional and loop initializers, so for your case it should be:

var fiveZeros = [for (var i = 0; i < 5; ++i) 0];

Everything becomes much flexible and powerful when you want to initialize by expression, not just constant:

var cubes = [for (var i = 0; i < 5; ++i) i * i * i];

is the same as [0, 1, 8, 27, 64].

Conditional elements are also essential taking into account the possibility to build a list of widgets where some of them depend on the state or platform.

More details here

score 4 · Answer 3 · answered May 30 '18 at 07:12

4

You can use the filled method like what @Edman answered. I just want to add one more way by using generate

final list = new List.filled(5, 0);
print(list);

final list1 =  new List.generate(5, (index) {
  return 0;
});
print(list1);

answered May 30 '18 at 07:12

Phuc Tran

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27

score 1 · Answer 4 · answered May 30 '18 at 07:16

1

Use List.generate method.

var list = List.generate(5, (i) => 'Z');

answered May 30 '18 at 07:16

Vinoth Kumar

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5
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How to repeat value of array in Flutter

4 Answers4