Collection constructor with collection initialzer

You can pass anything that is a valid constructor parameter. For example, List permits construction from any enumerable, so you can do this:

	string[] ab = new string[] { "a", "b" };
	List<string> abcd = new List<string>(ab) { "c", "d" };
	// abcd has four elements: "a" "b" "c" and "d"
	// Resulting list is { 1, 2, 3, 4, 5 }
	var list2 = new List<int>(list) { 4, 5 };
	// Resulting list is { 4, 2, 3 }
	var list3 = new List<int>(list) { [0] = 4 };
	string[] ab = new string[] { "a", "b" };
	List<string> abcd = new List<string>(ab) { "c", "d" };
	// abcd has four elements: "a" "b" "c" and "d"

view raw collectionInit.cs hosted with ❤ by GitHub

this combination notation is useful if you want to clone an existing collection and then make some tweaks to it.

Real world Use Case Linq Aggregation

Problem statement

We want to process numbers and categorized them into categories. This could be any data and we want to classify them based on requirement. Just to create small proof of concepts here is the sequence of numbers and idea is to classify them into even, odds and so on.

Solution Statement

Linq Aggregate with Union to show them all.

Class Diagram

Implementation Details

Number Class

Enum NumberType 

NumberGroup Classes

INumberGroup

NumberFilter Class

Composition Class

Main Calling Function

This is it!