1. forEach()

Runs a function on each element in the list

var fruits = [‘banana’, ‘pineapple’, ‘watermelon’];

fruits.forEach((fruit) => print(fruit)); // => banana pineapple watermelon

2. map()

Produces a new list after transforming each element in a given list

var mappedFruits = fruits.map((fruit) => ‘I love $fruit’).toList();

print(mappedFruits); // => ['I love banana', ‘I love pineapple’, ‘I love watermelon’]

3. contains()

Checks to confirm that the given element is in the list

var numbers = [1, 3, 2, 5, 4];

print(numbers.contains(2)); // => true

4. sort()

Order the elements based on the provided ordering function

numbers.sort((num1, num2) => num1 - num2); // => [1, 2, 3, 4, 5]

5. reduce(), fold()

Compresses the elements to a single value, using the given function

var sum = numbers.reduce((curr, next) => curr + next);

print(sum); // => 15 const initialValue = 10;

var sum2 = numbers.fold(initialValue, (curr, next) => curr + next);

print(sum2); // => 25

6. every()

Confirms that every element satisfies the test

List<Map<String, dynamic>> users = [

{ “name”: ‘John’, “age”: 18 },

{ “name”: ‘Jane’, “age”: 21 },

{ “name”: ‘Mary’, “age”: 23 },

]; var is18AndOver = users.every((user) => user[“age”] >= 18);

print(is18AndOver); // => true



var hasNamesWithJ = users.every((user) => user[“name”].startsWith('J'));

print(hasNamesWithJ); // => false

7. where(), firstWhere(), singleWhere()

Returns a collection of elements that satisfy a test.

// See #6 for users list

var over21s = users.where((user) => user[“age”] > 21);

print(over21s.length); // => 1 var nameJ = users.firstWhere((user) => user[“name”].startsWith(‘J’), orElse: () => null);

print(nameJ); // => {name: John, age: 18} var under18s = users.singleWhere((user) => user[“age”] < 18, orElse: () => null);

print(under18s); // => null

firstWhere() returns the first match in the list, while singleWhere() returns the first match provided there is exactly one match.

8. take(), skip()

Returns a collection while including or skipping elements

var fiboNumbers = [1, 2, 3, 5, 8, 13, 21];

print(fiboNumbers.take(3).toList()); // => [1, 2, 3]

print(fiboNumbers.skip(5).toList()); // => [13, 21]

print(fiboNumbers.take(3).skip(2).take(1).toList()); // => [3]

9. List.from()

Creates a new list from the given collection

var clonedFiboNumbers = List.from(fiboNumbers);

print(‘Cloned list: $clonedFiboNumbers’);

As of Dart 2.0, the new keyword is optional when instantiating objects.

10. expand()

Expands each element into zero or more elements

var pairs = [[1, 2], [3, 4]];

var flattened = pairs.expand((pair) => pair).toList();

print(‘Flattened result: $flattened’); // => [1, 2, 3, 4] var input = [1, 2, 3];

var duplicated = input.expand((i) => [i, i]).toList();

print(duplicated); // => [1, 1, 2, 2, 3, 3]

Conclusion

I hope this has been insightful and if this is your first exposure to Dart, read my first steps tutorial to grasp the basics. The example snippets for this article are available on DartPad.

I also run a YouTube channel teaching subscribers to develop full-stack applications with Dart. Become a subscriber to receive updates when new videos are released.

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And this concludes the tutorial. Thanks for reading.

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