Naturally

Natural sorting order library for .NET Standard

Supported frameworks:

• .NET Standard 1.6
• .NET Standard 2.0
• .NET Standard 2.1

See the .NET Standard page for more information about which .NET Framework and .NET Core versions these versions applies to.

How to use it

First install the package into your project, either using your IDE or other tooling, or using the following command:

Install-Package lvk.naturally

Then, to use it, anywhere you can specify a StringComparer instance you can now use one of the following:

• NaturalSortOrderStringComparer.CurrentCulture
• NaturalSortOrderStringComparer.CurrentCultureIgnoreCase
• NaturalSortOrderStringComparer.InvariantCulture
• NaturalSortOrderStringComparer.InvariantCultureIgnoreCase
• NaturalSortOrderStringComparer.Ordinal
• NaturalSortOrderStringComparer.OrdinalIgnoreCase

All of these correspond to the existing StringComparer.*, only with "natural sort order" rules applied.

(Note that the two InvariantCulture options above does not exist for .NET Standard 1.6 due to the corresponding options only being added to .NET Standard 2.0)

What is natural sort order

Natural sort order treats numbers as numbes and not as digits forming a text.

This impacts sorting when text contains numbers, such as the following items:

file10.txt
file2.txt
file1.txt
file11.txt

With "normal" sort order, using lexicographical ordering, these will be treated strictly as text, and thus 1<2 as characters will apply, resulting in the following sort order:

file1.txt
file10.txt
file11.txt
file2.txt

Even though 2 is less than 10 or 11, 2 as a character comes after 1 as a character.

With natural sort order applied, the order becomes more "natural" in terms of what we expect:

file1.txt
file2.txt
file10.txt
file11.txt

Special features

The natural sort order algorithm implemented by this library is as follows:

• Whitespace does not matter, unless that is the only difference, then less whitespace comes before more whitespace.

  Examples:

  • A 10 comes before A11
  • A10 comes before A 10

  This also includes both leading and trailing whitespace.

• All unicode characters that are reported by .NET to have a "numerical value" counts towards numerical comparison

  This includes fractions, such as ¾ and ½, which will be sorted correctly, so that 2½ ts sugar comes before 2¾ ts sugar