Sorting a numeric string

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Hi,
I am trying to sort the values which is actually a seminumeric string.When i try to sort the values using LINQ i cant able to get the proper sorted data.

Say.if i am sorting the value in ascending order{

VB

 "121212-1","121212-7","121212-6","121212-16",121212-4",
"121212-15",
"121212-14"

}
with the query .OrderBy(list => list)

I am getting the proper output.KIndly help me to sort the seminumeric number.

I ahve tried the solution provided here

[^]
but it didnot helped me...

Regards,
Hsakarp.

Posted 13-Aug-13 21:44pm

hsakarp

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3 solutions

Solution 3

The problem is that you are trying to sort strings as if they were numbers - that doesn't work, because the sort order is different. With strings, the sort order goes:

1
10
11
12
...
19
2
20
...

What you need to do is convert them to numbers are sort those. Probably, the best way is to use a class, but a quick and dirty method would be to do this:

C#

List<string> list = new List<string>(){ "121212-1","121212-7","121212-6","121212-16","121212-4","121212-15","121212-14"};
list = list.OrderBy(x => int.Parse(x.Split('-')[0])).ThenBy(x => int.Parse(x.Split('-')[1])).ToList();
foreach (string s in list)
    {
    Console.WriteLine(s);
    }

But you would need to be sure that every string was in the right format first or you will get null reference or parse errors!

Posted 13-Aug-13 22:20pm

OriginalGriff

Solution 2

(If I got you) you have to parse each 'seminumeric' item in order to separate the two numeric parts (e.g. "121212-1" => fn=121212, ln=1) and then order the items based on such numeric parts (first considering fn and then ln).
It should be pretty straightforward.

Posted 13-Aug-13 22:13pm

CPallini

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Maarten Kools · Accepted Answer · 2013-08-13T22:11:00

Solution 1

You'll have to split the strings and order them as integers, like so:

C#

IList<string> list = new List<string> 
    {
        "121212-1",
        "121212-7",
        "121212-6",
        "121212-16",
        "121212-4", 
        "121212-15", 
        "121213-14", 
        "121212-14"
    };
	
    Console.WriteLine("unsorted");
    foreach(string s in list) Console.WriteLine(s);

    /**
        Output:
        
        121212-1
        121212-7
        121212-6
        121212-16
        121212-4
        121212-15
        121213-14
        121212-14
    **/
    
    IList<string> sortedList = list
        .Select(s => s.Split(new[]{"-"}, StringSplitOptions.RemoveEmptyEntries))
        .OrderBy(a => Int32.Parse(a[0]))
        .ThenBy(a => Int32.Parse(a[1]))
        .Select(a => String.Join("-", a))
        .ToList();
    
    Console.WriteLine("sorted");
    foreach(string s in sortedList) Console.WriteLine(s);

    /**
        Ouput:
        
        121212-1
        121212-4
        121212-6
        121212-7
        121212-14
        121212-15
        121212-16
        121213-14
    **/

Posted 13-Aug-13 22:11pm

Maarten Kools

Updated 13-Aug-13 22:12pm

v2

Comments

CPallini 14-Aug-13 4:29am

5.

Nandakishore G N 14-Aug-13 5:10am

Good answer. +5..

hsakarp 14-Aug-13 7:05am

Thanks for quick reply..i have tried to replicate the same with my model class.while converting that into the list i ma getting the error "cannot convert the string to model class".I have tried changing the class also cant able to figure out the way to achieve..

Currently i am sorting the entire list with a column called activity

ASList
//.OrderBy(list => DateTime.Parse(list.CreatedDate))
//.OrderBy(list => list.ActivityID)
.Select(list => list.ActID.Split(new [] { "-" }, StringSplitOptions.RemoveEmptyEntries))
.OrderBy(a => Int32.Parse(a[0]))
.ThenBy(a => Int32.Parse(a[1]))
.Select(a => String.Join("-", a))
.OrderBy(list => DateTime.Parse(list.CreatedDate))
".ToList()";

If i change the string to the model class i dont have the access to the split option.could you share me the way to achieve this

Regards,
Hsakarp

Maarten Kools 14-Aug-13 7:26am

You're creating a list of Strings with the second Select. You'll have to write it differently if the string to sort is encapsulated in an object.

e.g.
var sortedList = (from i in list
let id = i.ActID.Split(new [] { "-" }, StringSplitOptions.RemoveEmptyEntries)
orderby Int32.Parse(id[0]), Int32.Parse(id[1])
select i)
.ToList()

hsakarp 14-Aug-13 8:04am

superbb!!!..

Many thanks..:)