Sort List Multiple properties alphabetically and numerically

Question

I have the following list with 3 columns. Column 3 is of type string, when trying to identify if it is an integer

Col1    Col2    Col3

0000    Item0   1
0000    Item0   10
0000    Item0   11
0000    Item0   12
0000    Item0   2
0000    Item0   3

0000    Item1   P1
0000    Item1   P10
0000    Item1   P11
0000    Item1   P12
0000    Item1   P2
0000    Item1   P3

when i try to sort it as follows, the last column is not sorted by field type

var orderedCustomers = Object.OrderBy(c => c.Col1).ThenBy(c => c.Col2).ThenBy(d => d.Col3);

Has anyone been through something similar, I want column 3 to be sorted asc but first numerically?

the result I am looking for is:

Col1    Col2    Col3

0000    Item0   1
0000    Item0   2
0000    Item0   3
0000    Item0   10
0000    Item0   11
0000    Item0   12

0000    Item1   P1
0000    Item1   P2
0000    Item1   P3
0000    Item1   P10
0000    Item1   P11
0000    Item1   P12

Does this answer your question? [Sorting List in C#](https://stackoverflow.com/questions/3716831/sorting-liststring-in-c-sharp) — gunr2171, Aug 14 '23 at 23:45
The usual trick: `.ThenBy(d => d.Col3.Length).ThenBy(d => d.Col3)`, will work if within Col1 and Col2 the prefixes are equal-lenght. — Gert Arnold, Aug 15 '23 at 09:12

Peter B · Accepted Answer · 2023-08-15T00:08:38.540

This can be done with a few helper methods to split and extract data from Col3.

First we take the non-numeric prefix (or "" if there isn't any) and sort by that.
Then we take the numeric suffix, convert it to an int value and sort by that as well. (I'm using int.MaxValue if there is no numeric suffix, you could use 0 or -1 if that suits you better)

var orderedCustomers = Object
   .OrderBy(c => c.Col1)
   .ThenBy(c => c.Col2)
   .ThenBy(d => TxtPart(d.Col3))
   .ThenBy(d => NumPart(d.Col3));

// Helper methods

public static string TxtPart(string s) => Regex.Match(s, @"^[^0-9]*").Value;

public static int NumPart(string s) => int.TryParse(Regex.Match(s, @"[0-9]*$").Value, out int v) ? v : int.MaxValue;

See this Fiddle: https://dotnetfiddle.net/bfVTSr

Output:

0000, Item0, 1
0000, Item0, 2
0000, Item0, 3
0000, Item0, 10
0000, Item0, 11
0000, Item0, 12
0000, Item1, P1
0000, Item1, P2
0000, Item1, P3
0000, Item1, P10
0000, Item1, P11
0000, Item1, P12

The helper method NumPart, how would the function be if it were in .net5? — Pollo, Aug 15 '23 at 02:03
My code works (tested) from .NET Core 3 (which comes with C# 8) and up, so that includes .NET 5 (C# 9). If you mean the ancient and almost obsolete .NET Framework (C# 6 or below), then you'll need to put the declaration of `v` outside of the `int.TryParse` call, as follows, using a regular function body: `public static int NumPart(string s) { int v; return int.TryParse(Regex.Match(s, @"[0-9]*$").Value, out v) ? v : int.MaxValue; }` — Peter B, Aug 15 '23 at 14:12

Sort List Multiple properties alphabetically and numerically

1 Answers1