How to return value from for loop using Dart

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I have the following for loop in Dart:

 Locations allLocations(AsyncSnapshot<Results> snap) {
    for (var i = 0; i < snap.data.locationList.length; i++) {
      return snap.data.locationList[i];
    }
  }

My goal is to iterate through the list of locations, which I'm getting through a snapshot, and then return each value. Unfortunately, the Dart analyzer is telling me, that this function doesn't end with a return statement. Well, I'm not sure what I'm doing wrong in this example.

I appreciate any help!

I think u want something like this

Stream<int> allInts(List<int> list) async* {
    for (var i = 0; i < list.length; i++) {
      yield list.elementAt(i);
    }
  }

And when i use this

allInts(<int>[1, 3, 5, 7, 9]).listen((number) {
  print(number);
});

Console:

I/flutter (24597): 1
I/flutter (24597): 3
I/flutter (24597): 5
I/flutter (24597): 7
I/flutter (24597): 9

How to return from a forEach loop in Dart?, 3 Answers. There is no way to return a value from forEach . Just use a for loop instead. For this specific use case, you can also use any() instead of forEach() , e.g. The for loop is an implementation of a definite loop. The for loop executes the code block for a specified number of times. It can be used to iterate over a fixed set of values, such as an array. Following is the syntax of the for loop. for (initial_count_value; termination-condition; step) { //statements } Example

try this:

 Locations allLocations(AsyncSnapshot<Results> snap) {
  List returnedList = new List();
  for (var i = 0; i < snap.data.locationList.length; i++) {
    returnedList.add(snap.data.locationList[i]);
  }
  return returnedList;
}

Dart Return Values | W3Schools | Tutorialspoint, In Dart, there is return keyword allows a function to return value. The return statement is optional, if not specified the function returns null. There can be only one� Dart Return Values Sometimes we may want a function to return some value to the point it where it is called from. In Dart, there is returnkeyword allows a function to return value. The returnstatement is optional, if not specified the function returns null.

You must not return value at every index, otherwise, the function will be returned at first index only and will not go through complete iteration. Rather, you should return complete list outside loop.

List<Locations> mList= new List();
Locations allLocations(AsyncSnapshot<Results> snap) {
for(var i in  snap.data.locationList){
      mList.add(return snap.data.locationList[i]);
  }
return snap.data.locationList;
}

Dart Programming - Returning Function, Dart Programming - Returning Function - Functions may also return value along with the In other words, there can be only one return statement per function. Dart for Loop. The for loop is used when we want to execute block of code known times. In Dart, basic for loop is similar as it is in C, C++ and Java. The for loop takes a variable as iterator and assign it with an initial value, and iterate through the loop body as long as the test condition is true. Once the loop statements are executed for current iteration, the iterator is updated with new value and if the test condition is still valid, we loop another time.

Iterable collections, How to map the contents of an Iterable to a different value. You can read the elements of an iterable sequentially, using a for-in loop. This method requires you to pass a predicate, which is a function that returns true if the input satisfies a � The syntax of for loop in dart looks like this. for (Initialization; Condition; Increment/Decrement) { // code block to be executed } Initialization is executed only once. The very first time when the for loop starts. Condition is checked every time. If the condition satisfies the loop code block will be executed.

Iterable class - dart:core library, If the call returns false , there are no more elements, and iterator.current returns null . The iterators of the same iterable should provide the same values in the same You can also iterate over the elements of an Iterable using the for-in loop � First the tap event occurs. The event loop gets the event, and it calls your tap handler (which you set using the onPressed parameter to the RaisedButton constructor). Your handler uses the http

Return two values, in Dart, Think of the most idiomatic way in the language to return the two values at the return Boolean is begin for K in M'Range (1) loop for L in M'Range (2) loop if M� Sr.No Loop & Description; 1: for loop. The for loop is an implementation of a definite loop. The for loop executes the code block for a specified number of times. It can be used to iterate over a fixed set of values, such as an array

Comments
  • What is Locations? Can you share Locations class
  • Location class consists of two parameters such as latitude and longitude. I'm loading a json file with information about locations therefore I have a snapshot of this loaded data. Now I want to show markers on google maps. In order to show every marker I need to iterate through the list of data.
  • A function call can only return once. Returning more than once is not meaningful, so it's not clear what it is you want to achieve. So, what is it that you actually want to achieve?
  • I'll be taking the approach from Ibrahim. What I want to achieve is, to read every data stored in a list and display it on the screen. I cannot just use a ListView.builder or similar because those are coordinates which represent points on a map
  • This is somewhat in the right direction. I think I can work with that. Thanks!
  • As I told Ravinder Kumar in the above comment. My snap.data.locationList is already a list. I don't want to return a complete list, but every value from the list. I need each individual value from the list because I want to display every value.
  • I'm not quite sure whether I understood your solution. My snap.data.locationListis already a list. I don't want to return a complete list, but every value from the list. I need each individual value from the list because I want to display every value.
  • if you use return inside a loop then return will exit the loop on very 1st index, I hope you get it.
  • I got that point. This doesn't solve my issue. I want to return every value from the list snap.data.locationList. When I'm copying your code into the IDE it complains that I'm using a return statement within my mList.add(). Also the iwithin the snap.data.locationList[i] is not a int type rather it is from type Location because you writing var i in snap.data.locationList. So there are might be some things wrong.
  • I have written this to to clear the concept. I did not write this in my IDE. Also if you want to display something than you must return a list from here and take a listview.count inside your build function.