var values =[{'userId':1, 'rating':4.5},
{'userId':2, 'rating':4.0},
{'userId':3, 'rating':3.5},
{'userId':4, 'rating':3.0}];
var result = values.map((m)=> m['rating']).reduce((a, b)=> a + b) / values.length;
print(result);
1. Dart is a Programmign language that mainly used for Flutter.
2. It's designed for client development, such as for the web and mobile apps.
3. Developed by Google
Dart is an open source, purely object-oriented, optionally typed, and a class-based language which has excellent support for functional as well as reactive programming. Unlike C# or Java, Dart is not bloated at all. In fact, it's a relatively simple, modern and highly efficient language to work with