Map and List are one of the most important concept for Dart and Flutter app development. Once you know the basics of Map and List, it will make your life easier.
We use List a lot internally flutter framework and you must to some basics ussage of List like declaring, adding and removing items from list.
5 Different ways to remove items from a List in Flutter Dart
List myList = [1,2,3,4,5];
myList.removeAt(2);
print(myList); // [1, 2, 4, 5]
print(myList.length); // 4So if you want to remove the first Item, then you will send 0 for removeAt().
removeAt(0) //removes the first item
removeAt(1) //removes the second item
List myList = [1,2,3,4,5];
bool result = myList.remove(2);
print(myList); // [1, 3, 4, 5]
print(result); // true
print(myList.length); // 4This is used often in flutter framework when you make a post request to remove items.
List myList = [1,2,3,4,5];
var result = myList.removeLast();
print(myList); // [1, 2, 3, 4]
print(result); // 5
print(myList.length); // 4
List myList = [1,2,3,4,5];
int howMany = 2;
myList.length = myList.length - howMany;
print(myList); // [1, 2, 3]
print(myList.length); // 3
List myList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
myList.removeWhere((item) => item % 2 == 0);
print(myList); // [1, 3, 5, 7, 9]
print(myList.length); // 5This one is super important in flutter programming.
Spread opeator and remove item
If you have list, and you want to update this using spread operator, then below is the way to go.
void removeAnItem(int index){
state.removeAt(index);
state = [...state];
}Here state is stateful list. In Flutter framework we use a stateful list all the time. Here we remove at item at first. Then this list would be auto updated.
but we also need to assign it state variable again. Otherwise UI won't get the latest value. So we assign it using spread operator.
The above kind of spread operator is used if you use Riverpod as state management system.
