NaturalSort

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About

Natural sort order is an ordering of strings in alphabetical order, except that multi-digit numbers are ordered as a single character. Natural sort order has been promoted as being more human-friendly ("natural") than the machine-oriented pure alphabetical order.

For example, in alphabethical sorting "z11" would be sorted before "z2" because "2" is sorted as smaller than "1", while in natural sorting "z2" is sorted as smaller than "z11" because "2" is sorted as smaller than "11".

Functionality to sort by natural sort order is built into many progamming languages and libraries.

Authors

Antônio Galvão and Rik van Kekem

Platforms

Linux and Windows.

Features

Two types of sorting

 type
   TSortType = (stNatural, stFloatThousand);

Topic numerators, integers and IP addresses are sorted by stNatural sort type. Thousand separated and floating point numbers are sorted by stFloatThousand sort type. Both make collated alphabetical order and sort internal numbers in alphabetical strings.

Collated alpha-numerical sorting (stNatural or stFloatThousand):

Alphabetical parts sorted by OS (Windows or Linux).

    0o3ö6ãrõxögùmî1ó5egõ
    1I8iuã0u4ô8EeU7öuOkü
    3â0á0e6ùsunueUtö8írò
    3áiokúdùsétöbïqãkôvI
    4õ4îcë4ò0à1ólOaUpáxã
    5î2ãgâoí8î4ü1ò3ïwowë
    5úrüqUfò5u0íyïfü5âlí

Topic enumerators sorting (stNatural):

    1
    1.1.1
    1.1.2
    1.2.1
    1.99.99
    2

Integers sorting (stNatural):

    0
    00
    000
    1
    2
    10

IP addresses sorting (stNatural):

    10.145.254.9
    10.145.255.9
    10.145.255.10
    10.146.254.9
    121.243.100.0
    255.255.255.254

Floating point numbers sorting (stFloatThousand):

    0,99
    1
    1,01
    1,99
    2

Thousand separated numbers sorting (stFloatThousand):

    1.198
    1.199
    1.199,50
    1.200
    1.201
    1.101.300

Thousand and decimal separators are the system default ones.

It is fast. See the time against other functions:

     StrCmpLogicalW: 1
    WideCompareText: 1,238
        NaturalSort: 0,746

Download

The latest version is available here: http://sourceforge.net/projects/lazarusfiles/files/naturalsort.zip/download

A demo project is included.

Functions and Procedures

procedure NaturalSort(aList: TStrings; SortType: TSortType);

This procedure provides a way to sort a list of TStrings directly, according to the chosen SortType, stFloatThousand (for floating point and thousand separators sort) or stNatural (for all other supported sorts).

Example of usage:

 procedure TForm1.Button1Click(Sender :TObject);
 begin
   NaturalSort(Memo1.Lines, stNatural); 
   NaturalSort(Memo2.Lines, stFloatThousand); 
 end;

function UTF8NaturalCompareList(aList: TStringList; Index1, Index2: Integer): Integer;

Example of usage:

 procedure NaturalSort(aList: TStrings);
 var
   L: TStringList;
 begin
   L := TStringList.Create;
   try
     L.Assign(aList);
     L.CustomSort(@UTF8NaturalCompareList);
     aList.Assign(L);
   finally
     L.Free;
   end;
 end;

function UTF8FloatThousandCompareList(aList: TStringList; Index1, Index2: Integer): Integer;

Example of usage:

 procedure FloatThousandSort(aList: TStrings);
 var
   L: TStringList;
 begin
   L := TStringList.Create;
   try
     L.Assign(aList);
     L.CustomSort(@UTF8FloatThousandCompareList);
     aList.Assign(L);
   finally
     L.Free;
   end;
 end;

Natural sort controls

A TNaturalListBox and a TNaturalComboBox are provided along with the demo project.