averageBy method
Example:
[1, 2, 3].averageBy((n) => n); // 2.0
['cat', 'horse'].averageBy((s) => s.length); // 4.0
Implementation
double? averageBy(num Function(T) selector) {
if (this.validate().isEmpty) {
return null;
}
return sumByDouble(selector) / this!.length;
}