For Each Loop in Dart

For Each Loop

The for each loop iterates over all list elements or variables. It is useful when you want to loop through list/collection. The syntax of for-each loop is:

collection.forEach(void f(value));

Example 1: Print Each Item Of List Using Foreach

This will print each name of football players.

void main(){
  List<String> footballplayers=['Ronaldo','Messi','Neymar','Hazard'];
  footballplayers.forEach( (names)=>print(names));
}

Ronaldo
Messi
Neymar
Hazard

Example 2: Print Each Total and Average Of Lists

This program will print the total sum of all numbers and also the average value from the total.

void main(){
  List<int> numbers = [1,2,3,4,5];
  
  int total = 0;
  
   numbers.forEach( (num)=>total= total+ num);
  
  print("Total is $total.");
  
  double avg = total / (numbers.length);
  
  print("Average is $avg.");
  
}

Total is 15.
Average is 3.

For In Loop In Dart

There is also another for loop, i.e., for in loop. It also makes looping over the list very easily.

void main(){
    List<String> footballplayers=['Ronaldo','Messi','Neymar','Hazard'];

  for(String player in footballplayers){
    print(player);
  }
}

Ronaldo
Messi
Neymar
Hazard

How to Find Index Value Of List

In dart, asMap method converts the list to a map where the keys are the index and values are the element at the index.

void main(){

List<String> footballplayers=['Ronaldo','Messi','Neymar','Hazard'];

footballplayers.asMap().forEach((index, value) => print("$value index is $index"));

}

Ronaldo index is 0
Messi index is 1
Neymar index is 2
Hazard index is 3

Example 3: Print Unicode Value of Each Character of String

This will split the name into Unicode values and then find characters from the Unicode value.

void main(){
  
String name = "John";
     
for(var codePoint in name.runes){
  print("Unicode of ${String.fromCharCode(codePoint)} is $codePoint.");
}
}

Unicode of J is 74.
Unicode of o is 111.
Unicode of h is 104.
Unicode of n is 110.

Video

Watch our video on for each loop in Dart.