sort string-numbers [duplicate]

Answer 1

Since this includes many string operations, regex etc., I don't think it is an efficient algorithm but It seems to work.

List list1 = new List() { "11c22", "1", "10", "11", "11a", "11b", "12", "2", "20", "21a", "21c", "A1", "A2" };
List list2 = new List() { "File (5).txt", "File (1).txt", "File (10).txt", "File (100).txt", "File (2).txt" };
var sortedList1 = NaturalSort(list1).ToArray();
var sortedList2 = NaturalSort(list2).ToArray();

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public static IEnumerable NaturalSort(IEnumerable list)
{
    int maxLen = list.Select(s => s.Length).Max();
    Func PaddingChar = s => char.IsDigit(s[0]) ? ' ' : char.MaxValue;

    return list
            .Select(s =>
                new
                {
                    OrgStr = s,
                    SortStr = Regex.Replace(s, @"(\d+)|(\D+)", m => m.Value.PadLeft(maxLen, PaddingChar(m.Value)))
                })
            .OrderBy(x => x.SortStr)
            .Select(x => x.OrgStr);
}