This tutorial shows you how to get the sum of all numbers in a `List`

using Dart.

If you have some numeric values stored in a `List`

, getting the sum of all values can be done in several ways. Below is a `List`

of integer values that we are going to get the sum of. You can also apply the methods below if the elements are a subtype of `num`

which include `int`

and `double`

.

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

## Using For Loop

For loop is a common way to iterate over an `Iterable`

. You can use it to get the sum of numbers. First, create a numeric variable to store the result. In each iteration, add the element to the variable using `+=`

operator.

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

Output:

` 15`

## Using Reduce

`reduce`

is a method that reduces the elements of an `Iterable`

to a single value by combining each element using a provided function. The function accepts two arguments. The first one is the accumulated value whose initial value is the first element. The other is the current element. In order to get the value, you can pass a function that returns the sum of the accumulated value and the current element.

```
var result = numbers.reduce((a, b) => a + b);
print(result);
```

Output:

` 15`

## Using Fold

`fold`

is similar to `reduce`

. The difference is it accepts an initial value as the first argument, while the accumulator function becomes the second argument.

```
var result = numbers.fold(0, (a, b) => a + b);
print(result);
```

Output:

` 15`

## Using `collection`

Extension

Dart team's `collection`

package has `IterableNumberExtension`

whose one of the properties is `sum`

. You can install the package by using `dart pub add collection`

(or `flutter pub add collection`

for Flutter).

By importing the collection library using `package:collection/collection.dart`

, you can use the `sum`

getter on any `Iterable`

of numbers.

` print(numbers.sum);`

Output:

` 15`

If you don't want to add an additional library. You can also create your own extension.

```
extension MyIterableNumberExtension on Iterable {
num get sum {
num sum = 0;
for (var n in this) {
sum += n;
}
return sum;
}
}
```

## Summary

Getting the sum of numeric elements can be done in several ways. All the methods in this tutorial should have the same complexity as they need to iterate over all the elements. You can choose the one that you prefer to be used in your code.

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