c#wpfsortingenumerable
Sorting a set of values with special characters
I have a task to sort a set of values in the DataTable. BUt the tricky part is that the values have special characters like '.' or '-' and negative values as well. The following picture is my current output:
the data are separated by ';' in the picture. I am using the following code to sort the data.
DataTable myDataTable = new DataTable();
myDataTable.Columns.Add("SN", typeof(string));
string myValues = "";
if (!File.Exists("d:\\DUDBC-values.txt")) //DUDBC-values.txt
{
Console.WriteLine("No file found");
Console.ReadKey();
return;
}
StreamReader file = new StreamReader("d:\\DUDBC-values.txt");
string line;
while ((line = file.ReadLine()) != null)
{
myValues += line;
myValues += ";";
}
file.Close();
string[] myValuesArray = myValues.Split(';');
myValuesArray = myValuesArray.Take(myValuesArray.Count() - 1).ToArray();
foreach (string myValue in myValuesArray)
{
DataRow myRow = myDataTable.NewRow();
myRow["SN"] = myValue;
myDataTable.Rows.Add(myRow);
}
string beforeSort = string.Join(";", myDataTable.AsEnumerable().Select(x => x["SN"]));
Console.WriteLine("Before Sorting:");
Console.WriteLine();
Console.WriteLine(beforeSort);
Console.WriteLine();
IEnumerable<DataRow> sortedValues = myDataTable.AsEnumerable()
.OrderBy(x =>
{
string currentStringValue = x["SN"].ToString();
char[] SplitChar = new char[] { '.', '-' };
string[] currentStringValueArray = new string[1];
try
{
float val = float.Parse(currentStringValue);
currentStringValueArray[0] = currentStringValue;
}
catch {
currentStringValueArray = currentStringValue.Split(SplitChar);
}
string currentPart = "";
int currentPartNumeric = 0;
if (currentStringValueArray.Length > 1)
{
for (int i = 0; i < currentStringValueArray.Length; i++)
{
if (int.TryParse(currentStringValueArray[i], out currentPartNumeric))
{
if (i >= 1)
currentPart += ".";
currentPart += currentPartNumeric.ToString();
}
else
{
try
{
if (i >= 1)
currentPart += ".";
currentPart += (((int)(char.ToUpper(char.Parse(currentStringValueArray[i])))) - 64).ToString();
}
catch { }
}
}
return Convert.ToString(currentPart, CultureInfo.InvariantCulture);
}
else
return 0m.ToString();
});
string afterSort = string.Join(";", sortedValues.Select(x => x["SN"]));
Console.WriteLine("After Sorting:");
Console.WriteLine();
Console.WriteLine(afterSort);
//Copy to your existing datatable
myDataTable = sortedValues.CopyToDataTable();
Console.ReadKey();
I was expecting it to be like this:
-1
1.1.a.1
1.2.a.1
1.2.a.2
1.2.a.3
1.3.1
2.1.2
2.1a.1
2.1a.2
2.5
2.6.1
2.7.1
2.7.2
2.7.16
2.25a
2.25b
2.42.1
2.42.2
3.1.1
3.1.2
3.5.2
3.6a.1
3.6a.2
3.6b.2
5.1a.1
5.1a.2
5.1a.3
5.1b.1
5.1b.2
5.1b.6
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.5.1
6.5.2-C11
6.5.3-C12
17.06.01.b.i
17.06.02.b.i
17.06.02.b.vi
18.01.b
18.02.01.b.iii
1000
What am i doing wrong? Help needed please. I had also asked this type of question in this post until users kept putting different types of values.
Solution
It looks like you need to sort in what's called "Natural sort order".
There is a Windows API function, StrCmpLogicalW() that you can use to do such a comparison.
You can wrap this in a set of extension methods for sorting List<T> or arrays like so:
public static class NaturalSortExt
{
/// <summary>Sorts a list in "Natural sort order", i.e. "9" sorts before "10".</summary>
/// <typeparam name="T">The type of elements in the list to be sorted.</typeparam>
/// <param name="self">The list to be sorted.</param>
/// <param name="stringSelector">A projection to convert list elements to strings for comparision.</param>
public static void SortNatural<T>(this List<T> self, Func<T, string> stringSelector)
{
self.Sort((lhs, rhs) => StrCmpLogicalW(stringSelector(lhs), stringSelector(rhs)));
}
/// <summary>Sorts a list in "Natural sort order", i.e. "9" sorts before "10".</summary>
/// <param name="self">The list to be sorted.</param>
public static void SortNatural(this List<string> self)
{
self.Sort(StrCmpLogicalW);
}
/// <summary>Sorts an array in "Natural sort order", i.e. "9" sorts before "10".</summary>
/// <param name="self">The array to be sorted.</param>
public static void SortNatural(this string[] self)
{
Array.Sort(self, StrCmpLogicalW);
}
[DllImport("shlwapi.dll", CharSet = CharSet.Unicode)]
static extern int StrCmpLogicalW(string lhs, string rhs);
}
Then you can just sort your array (or List<T>) as demonstrated in the sample code below:
class Program
{
static void Main()
{
string[] test =
{
"3.1.2",
"1.2.a.1",
"1.2.a.2",
"1.3.1",
"2.1.2",
"2.1a.2",
"2.1a.1",
"-1",
"2.5",
"2.7.1",
"1.1.a.1",
"2.7.16",
"2.7.2",
"2.25a",
"2.6.1",
"5.1a.3",
"2.42.2",
"2.25b",
"2.42.1",
"3.6a.2",
"5.1b.1",
"3.1.1",
"3.5.2",
"3.6a.1",
"3.6b.2",
"5.1a.1",
"1.2.a.3",
"5.1b.2",
"5.1b.6",
"6.3.1",
"6.3.2",
"17.06.02.b.i",
"6.3.3",
"5.1a.2",
"6.3.4",
"6.3.5",
"6.5.1",
"1000",
"6.5.2-C11",
"6.5.3-C12",
"17.06.01.b.i",
"17.06.02.b.vi",
"18.01.b",
"18.02.01.b.iii"
};
string[] expected =
{
"-1",
"1.1.a.1",
"1.2.a.1",
"1.2.a.2",
"1.2.a.3",
"1.3.1",
"2.1.2",
"2.1a.1",
"2.1a.2",
"2.5",
"2.6.1",
"2.7.1",
"2.7.2",
"2.7.16",
"2.25a",
"2.25b",
"2.42.1",
"2.42.2",
"3.1.1",
"3.1.2",
"3.5.2",
"3.6a.1",
"3.6a.2",
"3.6b.2",
"5.1a.1",
"5.1a.2",
"5.1a.3",
"5.1b.1",
"5.1b.2",
"5.1b.6",
"6.3.1",
"6.3.2",
"6.3.3",
"6.3.4",
"6.3.5",
"6.5.1",
"6.5.2-C11",
"6.5.3-C12",
"17.06.01.b.i",
"17.06.02.b.i",
"17.06.02.b.vi",
"18.01.b",
"18.02.01.b.iii",
"1000"
};
test.SortNatural();
Debug.Assert(test.SequenceEqual(expected));
Console.WriteLine(string.Join("\n", test));
}
}
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