Using lambda expression to solve the problem of C file name sorting (whether it is 100 or 11)

1、 The problem background ：

Sometimes you need to sort the list of output files , If used directly List<T>.Sort() When sorting methods , encounter 9, 10,11 and 100 The question of sequencing , There will be 2.xxx Greater than 100.xxx ( among ,xxx Represents the suffix of the file ) And so on , This is obviously not what we want to think .

in addition , In the same set of files , If all in : NNN_1_ABC.xxx,NNN_2_ABC.xxx……NNN_NNNN_ABC.xxx The form such as （ among N Is the number ）, here , stay NNN In the same case , We hope NNN_100 Than NNN_2  want “ Big ”.

For example, the following file list , It's direct use of List<T>.Sort() Method to sort ：

D:\ChineseCalendar\AI_ style \OK\00_CoverFM cover \00FM_01+ Round disc + vertical .svg
D:\ChineseCalendar\AI_ style \OK\00_CoverFM cover \00FM_02_ Kraft paper background + Snake circle calendar + Happy New Year! + Large small text advertisements + General advertising .svg
………………//  Here are some documents （ Next "//" Same as ）……………………
D:\ChineseCalendar\AI_ style \OK\00_CoverFM cover \00FM_19+ Colored leaves + curve + Advertisement on the upper left, middle right .svg
………………// ……………………
D:\ChineseCalendar\AI_ style \OK\02\02_ Children _ Blue sky, white clouds, sunflowers, etc 12 monthly calendar .svg
………………// ……………………
D:\ChineseCalendar\AI_ style \OK\09\09_ Upper left small picture + Top right lateral view + Lower left text advertisement + Single month calendar with week serial number in the lower right x12_OK.svg
D:\ChineseCalendar\AI_ style \OK\10\10_ Iron clip + Patterns on both sides + middle 12 Monthly calendar + Bottom ad .svg
………………// ……………………
D:\ChineseCalendar\AI_ style \OK\100\100_HappyFall+(2x2+4x2)=12 monthly calendar .svg
………………// ……………………
D:\ChineseCalendar\AI_ style \OK\109\109_ Gradient labels +3x2=6 Calendar... Half a month .svg
D:\ChineseCalendar\AI_ style \OK\11\11_Calendar Round sticker _OK.svg

We hope to be 0-9-10-11...100-101..200...201..., Instead of the above .

2、 resolvent ：

Post the code first ：

 /// <summary>
        /// Yes List<string> File list sorting
        /// </summary>
        /// <param name="listSvgFiles">List<string> File list sorting </param>
        /// <param name="isOrderByDesc"> Is it in reverse order? </param>
        /// <returns> Sorting result </returns>
        private static List<string> GetOrderListOfSvgFiles(List<string> listSvgFiles, bool isOrderByDesc)
        {
            // First use of Lambda The expressions are arranged in positive order
            List<string> orderedFile = (from s in listSvgFiles
                           let Split = s.Split('_')
                           let Str = Path.GetFileName(s)
                           where Str.IndexOf("FM") >= 0 || Regex.IsMatch(Str, @"\b\d+")
                           select s)
                   .OrderBy(x => int.Parse(Path.GetFileName(x).Split('_')[0].TrimEnd("FM".ToCharArray())))
                   .ThenBy(y => Path.GetFileName(y).Split('_')[1])
                   .ToList();
            // If the order is reversed
            if (isOrderByDesc)
            {
                orderedFile.Reverse();
            }

            return orderedFile;
        }

explain ： Bold text is used here to indicate the key points , meanwhile , If you have different needs , It can be modified according to the actual needs .

// Calling method ：

List<string> orderedFileList = GetOrderListOfSvgFiles(listSvgFiles, isOrderByDesc);

Last , Let's go through time . This is a recent calendar sample for the next few thousand years , Hey ！！