We will learn how to work with Lists using a variety of methods made available in the dart:core library. We will explore the top methods for working with List type collections.

Learn more about Lists at 

 

Array to list:

because .map return iterable.

var fruits = ['banana', 'pineapple', 'orange', 'watermelon', 'apple'];  var fiboNumbers = [1, 2, 3, 5, 8, 13, 21];  List

 

reduce vs fold:

reduce: doesn't provide the init value, but 'fold' does:

const initialValue = 10;  var sum2 = fiboNumbers.fold(initialValue, (curr, next) => curr + next);  print( sum2 );    var sum = fiboNumbers.reduce((curr, next) => curr + next);  print( sum );

 

filtering:

var over21s = users.where((user) => user['age'] > 21);  print( over21s.length );    var nameJ = users.firstWhere((user) => user['name'].startsWith('J'), orElse: () => null);  print( nameJ );    var under18 = users.singleWhere((user) => user['age'] < 18, orElse: () => {
   'error': 'Not Found'});  print( under18 );

 

take & skip:

print( fiboNumbers.take(3).toList() );  print( fiboNumbers.skip(5).toList() );  print( fiboNumbers.take(3).skip(2).take(1).toList() );

 

expend: the same as flatMap in JS

var flattened = [[1, 2], [3, 4]].expand((pair) => pair).toList();  print( flattened );    var duplicated = fiboNumbers.expand((i) => [i, i]).toList();  print( duplicated );