Re: Solution for sorting an array alpha-numerically

Thank you for the clarification, Lacey.

I admit that I had not seen the distinction that you are drawing, and I
appreciate the effort you put into describing it. I personally have not run
into this problem, but, by the effort you have gone to describe an answer,
it is clearly important for the applications that you create. I defer to
you on those requirements.

I suppose I would have solved the problems you describe by breaking the
strings up into groups and sorting the groups seperately, which is not
necessarily a better solution. For the kinds of data you are seeing, you
have a good answer.

I do not know if this kind of sorting is specifically "on the plate" for
anyone. If you'd like to see Microsoft implement any feature, I suggest
that you send that description to the MSWish@xxxxxxxxxxxxx e-mail address.
(perhaps package up your code and the solution below and send it in). You
could also submit an article to a developer magazine to describe your
problem and solution, or create a small project in GotDotNet.com to share
the code. These techniques make it easier for folks to find and reuse your
code than posting on a newsgroup.

Thanks again,
--
--- Nick Malik [Microsoft]
MCSD, CFPS, Certified Scrummaster
http://blogs.msdn.com/nickmalik

Disclaimer: Opinions expressed in this forum are my own, and not
representative of my employer.
I do not answer questions on behalf of my employer. I'm just a
programmer helping programmers.
--
"Lacey" <Lacey@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:CE9856AA-F8E2-42DB-8387-03C6D7DD59C3@xxxxxxxxxxxxxxxx
> Hi Nick,
>
> You and I are on two different topics. You are talking about lexographic
> sorting (like a dictionary) and I am talking about alphanumeric sorting.
> .NET Framework does not support alphanumeric sorting. (I'll prove it.
> Keep
> breathing, Nick! Grab some coffee!)
>
> Let's start with a definition for "alphanumeric sort": a re-ordering of
> data
> so that numeric and alphabetic data sort as seperate groups. This is
> unlike
> a "lexicographic sort" which re-orders data like a dictionary.
>
> I looked through the articles you suggested. In all the examples, the
> author either:
> 1. Compared strings that are completely numeric (for example: (int)"11"
> compared to (int)"2")
> 2. Compared strings that are completely alphabetic (for example: "John"
> compared to "Adam")
> 3. Or, displayed the same problem I solved:
> http://aspnet.4guysfromrolla.com/demos/ListArticles.aspx (See how
> "dgExample2.aspx" is listed after "dgExample19.aspx"?)
>
> None of these articles address the problem of alphanumeric sorting with
> mixed strings like "22Beers" versus "3Beers".
>
> For example, try this with the CompareTo method you suggested:
> int intCompare = "22Beers".CompareTo("3Beers");
> PROBLEM: The result is -1, meaning that "22Beers" < "3Beers". If we are
> doing an alphabetic comparison, this is correct. But if we are doing an
> alphanumeric comparison, this is incorrect because the number 22 is not
> less
> than the number 3.
>
> Let's look at a simple example with an array:
> 1. Create a web page with three labels (lblOriginal, lblLexo, lblAlphaNum)
> 2. In the Page_Load:
> string[] arrOriginal = {"a3", "a111", "a2", "a1", "a11", "a22"};
> for (int i = 0; i < arrOriginal.Length; i++ ) lblOriginal.Text +=
> (arrOriginal[i].ToString() + "<BR>");
>
> string[] arrLexo = {"a3", "a111", "a2", "a1", "a11", "a22"};
> Array.Sort(arrLexo);
> for (int j = 0; j < arrLexo.Length; j++ ) lblLexo.Text +=
> (arrLexo[j].ToString() + "<BR>");
>
> string[] arrAlphaNum = {"a3", "a111", "a2", "a1", "a11", "a22"};
> Array.Sort(arrAlphaNum, new AlphaNumCompare());
> for (int k = 0; k < arrAlphaNum.Length; k++ ) lblAlphaNum.Text +=
> (arrAlphaNum[k].ToString() + "<BR>");
>
> 3. To the same project as the web page, add the class AlphaNumCompare()
> which implements IComparer (provided in my previous posting).
>
> Run the page, and you'll see the problem.
> My original strings:
> a3
> a111
> a2
> a1
> a11
> a22
>
> Microsoft .NET sort:
> a1
> a11
> a111
> a2
> a22
> a3
>
> Custom alphanumeric sort:
> a1
> a2
> a3
> a11
> a22
> a111
>
> See how a11 is before a2 in the Lexographic sort? This is a common
> problem
> - getting string arrays to sort alphanumerically. I found a lot of
> postings
> from programmers also looking for solutions. For example, if I have an
> array
> of chapter titles for a book, my array needs to sort as:
> 1.1 Introduction
> 2.0 Procurement
> ...
> 2.9 Department-Specific Accounting
> 2.10 Delivery Addresses
> 3.0 Forms
>
> You may want to check out this article from Microsoft which says "The .NET
> Framework supports word [culture-sensitive comparison of strings], string
> [similar to a word sort, except that there are no special cases], and
> ordinal
> sort [compares the numeric value of each character; for example, a = 65]
> rules." Note that it does not have any mention of comparing strings with
> both alphabetic and numeric character and treating these character types
> as
> seperate groups:
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemstringclasstopic.asp)
>
> I hope Microsoft soon includes support for alphanumeric sorting of
> strings.
>
> Lacey
>
> "Nick Malik [Microsoft]" wrote:
>
>> Fascinating.
>>
>> You make the following statement:
>> > .NET does not support alphanumeric sort of arrays.
>>
>> This is simply not true. For your example, you simply have to implement
>> IComparable for your complex type, you don't need to implement a string
>> comparison. That is built in.
>>
>> In other words, you could replace the line:
>> > return CompareAlphaNum(a, b);
>>
>> with
>> return a.CompareTo(b);
>>
>> and delete the entire "CompareAlphaNum" routine.
>>
>>
>> Note that the CompareAlphaNum routine below doesn't use the same
>> collation
>> order that .Net uses. Perhaps you meant that .Net doesn't sort a capital
>> 'Z' in front of a lowercase 'a'. If that is what you meant, you are
>> right.
>> However, it is patently false to say that .Net doesn't support
>> alphanumeric
>> sorting.
>>
>> Some reference articles for you to read:
>> http://msdn.microsoft.com/library/en-us/cpref/html/frlrfsystemarrayclasssorttopic3.asp
>> http://odetocode.com/Articles/203.aspx
>> http://www.devx.com/dotnet/Article/21089
>> http://aspnet.4guysfromrolla.com/articles/060403-1.aspx
>>
>> --
>> --- Nick Malik [Microsoft]
>> MCSD, CFPS, Certified Scrummaster
>> http://blogs.msdn.com/nickmalik
>>
>> Disclaimer: Opinions expressed in this forum are my own, and not
>> representative of my employer.
>> I do not answer questions on behalf of my employer. I'm just a
>> programmer helping programmers.
>> --
>> "Lacey" <Lacey@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> news:1190A7FA-8A5A-41F2-82EA-5E45D1C257AA@xxxxxxxxxxxxxxxx
>> > .NET does not support alphanumeric sort of arrays. (I hope that
>> > changes
>> > soon!) Meanwhile, here is a solution.
>> >
>> > You could use this in your listbox by sorting the items in an array and
>> > then
>> > adding the array items from 0 to length to your listbox.
>> >
>> > 1. Create a custom comparer class that implements IComparer:
>> > using System;
>> > using System.IO;
>> >
>> > namespace Test1CSharp
>> > {
>> > /// <summary>
>> > /// Lacey Orr
>> > /// 29 June 2005
>> > /// Alpha-numeric sorting solution.
>> > /// </summary>
>> >
>> > public class AlphaNumCompare : System.Collections.IComparer
>> > {
>> > public int Compare(Object a1, Object b1)
>> > {
>> > //In my case, I compared Directory objects. So I took
>> > out
>> > // the filenames / foldernames from the parameter
>> > objects and
>> > // passed those to the sort.
>> >
>> > //The string variables to compare
>> > string a = "";
>> > string b = "";
>> >
>> > //Is a1 a FileInfo?
>> > if (a1.GetType() == System.Type.GetType("FileInfo"))
>> > a = ((FileInfo)a1).Name;
>> > else
>> > a = a1.ToString();
>> >
>> > //Is b1 a FileInfo?
>> > if (b1.GetType() == System.Type.GetType("FileInfo"))
>> > b = ((FileInfo)b1).Name;
>> > else
>> > b = b1.ToString();
>> >
>> > return CompareAlphaNum(a, b);
>> > }
>> >
>> > // CompareAlphaNum: Does an alphabetic sort.
>> > private static int CompareAlphaNum (string a, string
>> > b)
>> > {
>> > //Do a quick check for empty strings. If one
>> > string
>> > is empty, then we
>> > // can get out without doing any work.
>> >
>> > if (a.Length == 0 && b.Length > 0)
>> > return -1;
>> > else if (a.Length > 0 && b.Length == 0)
>> > return 1;
>> > else if (a.Length == 0 && b.Length == 0)
>> > return 0;
>> >
>> > //The order of chars - make this however you
>> > want.
>> > string strNums = "0123456789";
>> > string strSortOrder = "
>> > .!#$%&'()*+,-/:;<=>?@[]^_{}~0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
>> >
>> > //Variables for comparing
>> > bool aSmaller = true;
>> > bool isFound = false;
>> > int intIndex = 0;
>> > // intLength determines the number of times to
>> > loop.
>> > We will loop
>> > // until we hit the end of the shorter
>> > string -
>> > a
>> > or b.
>> > int intLength = (a.Length < b.Length? a.Length:
>> > b.Length);
>> > string strNumA = "";
>> > string strNumB = "";
>> > int numA = 0;
>> > int numB = 0;
>> > int j = 0;
>> > int k = 0;
>> >
>> > //Do the compare while we are not at the end of
>> > either string and haven't found
>> > // the result.
>> > while (!isFound && intIndex < intLength)
>> > {
>> > // if we are dealing with numbers, then
>> > sort
>> > the numbers numerically
>> > if (strNums.IndexOf(a[intIndex]) > -1 &&
>> > strNums.IndexOf(b[intIndex]) > -1)
>> > {
>> > //Get all the numbers in string A
>> > until
>> > we hit a non-number
>> > j = intIndex;
>> > while (j < a.Length &&
>> > strNums.IndexOf(a[j]) > -1)
>> > {
>> > strNumA += a[j].ToString();
>> > j++;
>> > }
>> > //Get all the numbers in string B
>> > until
>> > we hit a non-number
>> > k = intIndex;
>> > while (k < b.Length &&
>> > strNums.IndexOf(b[k]) > -1)
>> > {
>> > strNumB += b[k].ToString();
>> > k++;
>> > }
>> >
>> > numA = Convert.ToInt32(strNumA);
>> > numB = Convert.ToInt32(strNumB);
>> >
>> > if (numA < numB) // a is before b in
>> > sort order; a < b
>> > return -1;
>> > else if (numA > numB) // b is before
>> > a
>> > in sort order; a > b
>> > return 1;
>> > else if (numA == numB)
>> > {
>> > //The numbers are the same.
>> > Remove the number part from the strings
>> > // and compare the
>> > remainder
>> > of
>> > the string.
>> > return
>> > CompareAlphaNum(a.Substring(strNumA.Length, a.Length-strNumA.Length),
>> > b.Substring(strNumB.Length, b.Length-strNumB.Length));
>> > }
>> > }
>> > else
>> > {
>> > if
>> > (strSortOrder.IndexOf(b[intIndex]) <
>> > strSortOrder.IndexOf(a[intIndex]))
>> > {
>> > // If string a < b in a sort,
>> > then
>> > we're done
>> > aSmaller = false;
>> > isFound = true;
>> > }
>> > else if
>> > (strSortOrder.IndexOf(b[intIndex]) > strSortOrder.IndexOf(a[intIndex]))
>> > {
>> > // If string a > b in a sort,
>> > then
>> > we're done
>> > aSmaller = true;
>> > isFound = true;
>> > }
>> > else if (( b.Length < a.Length) &&
>> > (intIndex == intLength - 1))
>> > {
>> > // If the strings are equal up
>> > to
>> > the length-th char but a is longer,
>> > // then we're done.
>> > aSmaller = false;
>> > isFound = true;
>> > }
>> > else
>> > {
>> > // Otherwise, keep sorting
>> > intIndex ++;
>> > }
>> > }
>> > }
>> >
>> > if ((a.Length == b.Length) && !isFound)
>> > return 0; //strings are the same.
>> > else if (aSmaller)
>> > return -1; // a is before b in sort order;
>> > a
>> > < b
>> > else
>> > return 1; // b is before a in sort order;
>> > ; a
>> >> b
>> > }
>> > }
>> > }
>> >
>> >
>> > 2. Use the custom class using Array.Sort(myArray, new
>> > MyCompareClass()).
>> >
>> > a. Add a new web page
>> >
>> > b. Add:
>> > using System.IO;
>> > using System.Text;
>> >
>> > c. Add a label to the form (lblDir) to display the sort
>> >
>> > d. In the page load:
>> >
>> > private void Page_Load(object sender, System.EventArgs e)
>> > {
>> > //Get files in dir
>> > String strDir = MapPath("~/./");
>> > DirectoryInfo curDir = new DirectoryInfo(strDir);
>> > FileInfo [] fiArray = curDir.GetFiles();
>> > string [] strFilenames = new string[fiArray.Length];
>> > for (int j = 0; j < fiArray.Length; j++)
>> > {
>> > strFilenames[j] = fiArray[j].Name;
>> > }
>> >
>> > // Sort files
>> > Array.Sort(strFilenames, new AlphaNumCompare());
>> >
>> > //Display files
>> > StringBuilder sbFiles = new StringBuilder();
>> > for (int k = 0; k < strFilenames.Length; k++)
>> > {
>> > sbFiles.Append(strFilenames[k] + "<BR>");
>> > }
>> > lblDir.Text = sbFiles.ToString();
>> > }
>> >
>> > Lacey
>> >
>> > "Federico G. Babelis" wrote:
>> >
>> >> Hi All:
>> >>
>> >> I have this line of code, but the syntax check in VB.NET 2003 and also
>> >> in
>> >> VB.NET 2005 Beta 2 shows as unknown:
>> >>
>> >> Dim local4 As Byte
>> >>
>> >> Fixed(local4 = AddressOf dest(offset))
>> >>
>> >> CType(local4, Short) = CType(src, Short)
>> >>
>> >> Return
>> >>
>> >> End Fixed
>> >>
>> >> What is the "FIXED and END FIXED" and how the syntax error can be
>> >> "fixed"
>> >> ???
>> >>
>> >> Thx,
>> >>
>> >> Federico
>> >>
>> >>
>> >>
>>
>>
>>


.

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