CLSS.ExtensionMethods.IList.FillBy

Problem

Array.Fill is a convenient method to fill an array first introduced in .NET Standard 2.1. It has the following drawbacks:

• It is not available in .NET runtime environments earlier than .NET Standard 2.1, which are most of the .NET runtime environments. Learn more about the availability of .NET Standard 2.1 here.
• It only supports filling with a value, not with a factory function.
• It only supports raw arrays.
• It returns void and therefore is not very friendly to a functional-style call chain.

Solution

This package provides FillBy to all IList<T> types for .NET Standard 1.0 & 2.0. It rectified the above drawbacks.

Filling a List<T> with a factory function, passing through the element's index number:

using CLSS;
using System.Linq;

var numbers = Enumerable.Repeat(0, 5).ToList();
numbers.FillBy(i => i * i); // { 0, 1, 4, 9, 16, }

FillBy returns source collection, saving some lines of code and functional-style friendly:

using CLSS;
using System.Linq;

// Create and fill array the standard way
var numbers1 = new int[5];
Array.Fill(numbers1, 4);

// Create and fill array with FillBy
var numbers2 = new int[5].FillBy(4);

// Easy functional syntax
bool allValid = new int[5].FillBy(FactoryFunction)
  .Append(existingResults)
  .All(VerifyResult);

Note: ExclusiveSample works on all types implementing the IList<T> interface, including raw C# array.

This package is a part of the C# Language Syntactic Sugar suite.