How do I sort a two-dimensional rectangular array in C

Question

I have a two-dimensional array  of Strings  which make up my data table  of rows and columns    I want to sort this array by any column   I tried to find an algorithm for doing this in C   but have not been successful   Any help is appreciated

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If you could get the data as a generic tuple when you read it in or retrieved it  it would be a lot easier  then you would just have to write a Sort function that compares the desired column of the tuple  and you have a single dimension array of tuples

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Here is an archived article from Jim Mischel at InformIt that handles sorting for both rectangular and jagged multi-dimensional arrays

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Load your two-dimensional string array into an actual DataTable  System Data DataTable   and then use the DataTable object s Select   method to generate a sorted array of DataRow objects  or use a DataView for a similar effect       assumes stringdata row  col  is your 2D string array DataTable dt   new DataTable       assumes first row contains column names  for  int col   0  col  lt  stringdata GetLength 1   col          dt Columns Add stringdata 0  col         load data from string array to data table  for  rowindex   1  rowindex  lt  stringdata GetLength 0   rowindex          DataRow row   dt NewRow        for  int col   0  col  lt  stringdata GetLength 1   col                  row col    stringdata rowindex  col             dt Rows Add row        sort by third column  DataRow   sortedrows   dt Select      3       sort by column name  descending  sortedrows   dt Select      COLUMN3 DESC      You could also write your own method to sort a two-dimensional array   Both approaches would be useful learning experiences  but the DataTable approach would get you started on learning a better way of handling tables of data in a C  application

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Try this out   The basic strategy is to sort the particular column independently and remember the original row of the entry   The rest of the code will cycle through the sorted column data and swap out the rows in the array   The tricky part is remembing to update the original column as the swap portion will effectively alter the original column             public class Pair lt T gt                public int Index              public T Value              public Pair int i  T v                    Index   i                  Value   v                                  static IEnumerable lt Pair lt T gt  gt  Iterate lt T gt  this IEnumerable lt T gt  source                int index   0              foreach   var cur in source                    yield return new Pair lt T gt  index cur                   index                                    static void Sort2d string     source  IComparer comp  int col                var colValues   source Iterate                    Select x    new Pair lt string gt  x Index source x Index  col    ToList                colValues Sort  l r     comp Compare l Value  r Value                var temp   new string source 0  Length               var rest   colValues Iterate                while   rest Any                       var pair   rest First                    var cur   pair Value                  var i   pair Index                  if  i    cur Index                         rest   rest Skip 1                       continue                                     Array Copy source i   temp  temp Length                   Array Copy source cur Index   source i   temp Length                   Array Copy temp  source cur Index   temp Length                   rest   rest Skip 1                   rest Where x   gt  x Value Index    i  First   Value Index   cur Index                                   public static void Test1                 var source   new string                                    new string     foo    bar    4                     new string      jack    dog    1                     new string     boy    ball    2                     new string     yellow    green    3                               Sort2d source  StringComparer Ordinal  2

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This code should do what you are after  I haven t generalised it for n by n  but that is straight forward  That said - I agree with MusiGenesis  using another object that is a little better suited to this  especially if you intend to do any sort of binding    I found the code here   string     array   new string 3      array 0    new string 3     apple    apple    apple     array 1    new string 3     banana    banana    dog     array 2    new string 3     cat    hippo    cat               for  int i   0  i  lt  3  i         Console WriteLine String Format   0   1   2    array i  0   array i  1   array i  2        int j   2   Array Sort array  delegate object   x  object   y          return  x j  as IComparable  CompareTo y  j             for  int i   0  i  lt  3  i        Console WriteLine String Format   0   1   2    array i  0   array i  1   array i  2

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So your array is structured like this  I m gonna talk in pseudocode because my C -fu is weak  but I hope you get the gist of what I m saying   string values rows  columns    So value 1  3  is the value at row 1  column 3   You want to sort by column  so the problem is that your array is off by 90 degrees   As a first cut  could you just rotate it   std  string values by column columns  rows    for  int i   0  i  lt  rows  i      for  int j   0  j  lt  columns  j        values by column column  row    values row  column   sort array values by column column    for  int i   0  i  lt  rows  i      for  int j   0  j  lt  columns  j        values row  column    values by column column  row    If you know you only want to sort one column at a time  you could optimize this a lot by just extracting the data you want to sort     string values to sort rows    for  int i   0  i  lt  rows  i        values to sort i    values i  column to sort     sort array values to sort     for  int i   0  i  lt  rows  i        values i  column to sort    values to sort i    In C   you could play tricks with how to calculate offsets into the array  since you could treat your two-dimensional array as a one-d array  but I m not sure how to do that in c

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I like the DataTable approach proposed by MusiGenesis above  The nice thing about it is that you can sort by any valid SQL  order by  string that uses column names  e g   x  y desc  z  for  order by x  y desc  z    FWIW  I could not get it to work using column ordinals  e g   3 2 1   for  order by 3 2 1   I used only integers  but clearly you could add mixed type data into the DataTable and sort it any which way   In the example below  I first loaded some unsorted integer data into a tblToBeSorted in Sandbox  not shown   With the table and its data already existing  I load it  unsorted  into a 2D integer array  then to a DataTable  The array of DataRows is the sorted version of DataTable  The example is a little odd in that I load my array from the DB and could have sorted it then  but I just wanted to get an unsorted array into C  to use with the DataTable object   static void Main string   args        SqlConnection cnnX   new SqlConnection  Data Source r90jroughgarden   Initial Catalog Sandbox Integrated Security True        SqlCommand cmdX   new SqlCommand  select   from tblToBeSorted   cnnX       cmdX CommandType   CommandType Text      SqlDataReader rdrX   null      if  cnnX State    ConnectionState Closed  cnnX Open         int    aintSortingArray   new int 100  4         i  elementid  planid  timeid      try                 Load unsorted table data from DB to array         rdrX   cmdX ExecuteReader            if   rdrX HasRows  return           int i   -1          while  rdrX Read    amp  amp  i  lt  100                        i                aintSortingArray i  0    rdrX GetInt32 0               aintSortingArray i  1    rdrX GetInt32 1               aintSortingArray i  2    rdrX GetInt32 2               aintSortingArray i  3    rdrX GetInt32 3                     rdrX Close             DataTable dtblX   new DataTable            dtblX Columns Add  ChangeID            dtblX Columns Add  ElementID            dtblX Columns Add  PlanID            dtblX Columns Add  TimeID            for  int j   0  j  lt  i  j                          DataRow drowX   dtblX NewRow                for  int k   0  k  lt  4  k                                  drowX k    aintSortingArray j  k                             dtblX Rows Add drowX                      DataRow   adrowX   dtblX Select      ElementID  PlanID  TimeID            adrowX   dtblX Select      ElementID desc  PlanID asc  TimeID desc               catch  Exception ex                string strErrMsg   ex Message            finally               if  cnnX State    ConnectionState Open  cnnX Close

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Load your two-dimensional string array into an actual DataTable  System Data DataTable   and then use the DataTable object s Select   method to generate a sorted array of DataRow objects  or use a DataView for a similar effect       assumes stringdata row  col  is your 2D string array DataTable dt   new DataTable       assumes first row contains column names  for  int col   0  col  lt  stringdata GetLength 1   col          dt Columns Add stringdata 0  col         load data from string array to data table  for  rowindex   1  rowindex  lt  stringdata GetLength 0   rowindex          DataRow row   dt NewRow        for  int col   0  col  lt  stringdata GetLength 1   col                  row col    stringdata rowindex  col             dt Rows Add row        sort by third column  DataRow   sortedrows   dt Select      3       sort by column name  descending  sortedrows   dt Select      COLUMN3 DESC      You could also write your own method to sort a two-dimensional array   Both approaches would be useful learning experiences  but the DataTable approach would get you started on learning a better way of handling tables of data in a C  application

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I know its late but here is my thought you might wanna consider   for example this is array    m m m a a a b b b j j j k l m     and you want to convert it by column number 2  then   string   newArr   new string arr length  for int a 0 a lt arr length a        newArr a    arr a  1    a      create new array that contains index number at the end and also the column values Array Sort newArr   for int a 0 a lt newArr length a          int index   Convert ToInt32 newArr a  newArr a  Length -1          swap whole row with tow at current index     if index    a                string   arr2   arr a           arr a    arr index           arr index    arr2            Congratulations you have sorted the array by desired column  You can edit this to make it work with other data types

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This code should do what you are after  I haven t generalised it for n by n  but that is straight forward  That said - I agree with MusiGenesis  using another object that is a little better suited to this  especially if you intend to do any sort of binding    I found the code here   string     array   new string 3      array 0    new string 3     apple    apple    apple     array 1    new string 3     banana    banana    dog     array 2    new string 3     cat    hippo    cat               for  int i   0  i  lt  3  i         Console WriteLine String Format   0   1   2    array i  0   array i  1   array i  2        int j   2   Array Sort array  delegate object   x  object   y          return  x j  as IComparable  CompareTo y  j             for  int i   0  i  lt  3  i        Console WriteLine String Format   0   1   2    array i  0   array i  1   array i  2

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Can I check - do you mean a rectangular array      or a jagged array          It is quite easy to sort a jagged array  I have a discussion on that here  Obviously in this case the Comparison lt T gt  would involve a column instead of sorting by ordinal - but very similar   Sorting a rectangular array is trickier    I d probably be tempted to copy the data out into either a rectangular array or a List lt T   gt   and sort there  then copy back   Here s an example using a jagged array   static void Main         could just as easily be string        int     data   new int                new int    1 2 3            new int    2 3 4            new int    2 4 1               Sort lt int gt  data  2       private static void Sort lt T gt  T     data  int col          Comparer lt T gt  comparer   Comparer lt T gt  Default      Array Sort lt T   gt  data   x y    gt  comparer Compare x col  y col           For working with a rectangular array    well  here is some code to swap between the two on the fly     static T     ToJagged lt T gt  this T    array        int height   array GetLength 0   width   array GetLength 1       T     jagged   new T height          for  int i   0  i  lt  height  i                  T   row   new T width           for  int j   0  j  lt  width  j                          row j    array i  j                     jagged i    row            return jagged    static T    ToRectangular lt T gt  this T     array        int height   array Length  width   array 0  Length      T    rect   new T height  width       for  int i   0  i  lt  height  i                  T   row   array i           for  int j   0  j  lt  width  j                          rect i  j    row j                       return rect       fill an existing rectangular array from a jagged array static void WriteRows lt T gt  this T    array  params T     rows        for  int i   0  i  lt  rows Length  i                  T   row   rows i           for  int j   0  j  lt  row Length  j                          array i  j    row j

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This is an old question  but here s a class I just built based on the article from Jim Mischel at InformIt linked by Doug L   class Array2DSort   IComparer lt int gt           maintain a reference to the 2-dimensional array being sorted     string     sortArray      int    tagArray      int  sortIndex       protected string    SortArray   get   return  sortArray              constructor initializes the sortArray reference     public Array2DSort string    theArray  int sortIndex                 sortArray   theArray           tagArray   new int  sortArray GetLength 0            for  int i   0  i  lt   sortArray GetLength 0     i   tagArray i    i           sortIndex   sortIndex             public string    ToSortedArray                 Array Sort  tagArray  this           string    result   new string               sortArray GetLength 0    sortArray GetLength 1            for  int i   0  i  lt   sortArray GetLength 0   i                          for  int j   0  j  lt   sortArray GetLength 1   j                                  result i  j     sortArray  tagArray i   j                                   return result                x and y are integer row numbers into the sortArray     public virtual int Compare int x  int y                if   sortIndex  lt  0  return 0          return CompareStrings x  y   sortIndex              protected int CompareStrings int x  int y  int col                return  sortArray x  col  CompareTo  sortArray y  col              Given an unsorted 2D array data of arbitrary size that you want to sort on column 5 you just do this           Array2DSort comparer   new Array2DSort data  5           string    sortedData   comparer ToSortedArray      Note the virtual Compare method and protected SortArray so you can create specialized subclasses that always sort on a particular column or do specialized sorting on multiple columns or whatever you want to do  That s also why CompareStrings is broken out and protected - any subclasses can use it for simple comparisons instead of typing out the full SortArray x  col  CompareTo SortArray y  col   syntax

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Can I check - do you mean a rectangular array      or a jagged array          It is quite easy to sort a jagged array  I have a discussion on that here  Obviously in this case the Comparison lt T gt  would involve a column instead of sorting by ordinal - but very similar   Sorting a rectangular array is trickier    I d probably be tempted to copy the data out into either a rectangular array or a List lt T   gt   and sort there  then copy back   Here s an example using a jagged array   static void Main         could just as easily be string        int     data   new int                new int    1 2 3            new int    2 3 4            new int    2 4 1               Sort lt int gt  data  2       private static void Sort lt T gt  T     data  int col          Comparer lt T gt  comparer   Comparer lt T gt  Default      Array Sort lt T   gt  data   x y    gt  comparer Compare x col  y col           For working with a rectangular array    well  here is some code to swap between the two on the fly     static T     ToJagged lt T gt  this T    array        int height   array GetLength 0   width   array GetLength 1       T     jagged   new T height          for  int i   0  i  lt  height  i                  T   row   new T width           for  int j   0  j  lt  width  j                          row j    array i  j                     jagged i    row            return jagged    static T    ToRectangular lt T gt  this T     array        int height   array Length  width   array 0  Length      T    rect   new T height  width       for  int i   0  i  lt  height  i                  T   row   array i           for  int j   0  j  lt  width  j                          rect i  j    row j                       return rect       fill an existing rectangular array from a jagged array static void WriteRows lt T gt  this T    array  params T     rows        for  int i   0  i  lt  rows Length  i                  T   row   rows i           for  int j   0  j  lt  row Length  j                          array i  j    row j

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If you could get the data as a generic tuple when you read it in or retrieved it  it would be a lot easier  then you would just have to write a Sort function that compares the desired column of the tuple  and you have a single dimension array of tuples

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So your array is structured like this  I m gonna talk in pseudocode because my C -fu is weak  but I hope you get the gist of what I m saying   string values rows  columns    So value 1  3  is the value at row 1  column 3   You want to sort by column  so the problem is that your array is off by 90 degrees   As a first cut  could you just rotate it   std  string values by column columns  rows    for  int i   0  i  lt  rows  i      for  int j   0  j  lt  columns  j        values by column column  row    values row  column   sort array values by column column    for  int i   0  i  lt  rows  i      for  int j   0  j  lt  columns  j        values row  column    values by column column  row    If you know you only want to sort one column at a time  you could optimize this a lot by just extracting the data you want to sort     string values to sort rows    for  int i   0  i  lt  rows  i        values to sort i    values i  column to sort     sort array values to sort     for  int i   0  i  lt  rows  i        values i  column to sort    values to sort i    In C   you could play tricks with how to calculate offsets into the array  since you could treat your two-dimensional array as a one-d array  but I m not sure how to do that in c

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using System  using System Collections Generic  using System Linq  using System Text   namespace ConsoleApplication1       class Program               static void Main string   args                        int    arr       20  9  11      30  5  6                  Console WriteLine  before                for  int i   0  i  lt  arr GetLength 0   i                                  for  int j   0  j  lt  arr GetLength 1   j                                          Console Write   0 3    arr i  j                                      Console WriteLine                              Console WriteLine  After                 for  int i   0  i  lt  arr GetLength 0   i       Array Sorting                               for  int j   arr GetLength 1  - 1  j  gt  0  j--                                         for  int k   0  k  lt  j  k                                                  if  arr i  k   gt  arr i  k   1                                                         int temp   arr i  k                               arr i  k    arr i  k   1                               arr i  k   1    temp                                                                                    Console WriteLine                               for  int i   0  i  lt  arr GetLength 0   i                                  for  int j   0  j  lt  arr GetLength 1   j                                          Console Write   0 3    arr i  j                                      Console WriteLine

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Here is an archived article from Jim Mischel at InformIt that handles sorting for both rectangular and jagged multi-dimensional arrays

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Here is an archived article from Jim Mischel at InformIt that handles sorting for both rectangular and jagged multi-dimensional arrays

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Array Sort array   a  b       return a 0  - b 0

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Try this out   The basic strategy is to sort the particular column independently and remember the original row of the entry   The rest of the code will cycle through the sorted column data and swap out the rows in the array   The tricky part is remembing to update the original column as the swap portion will effectively alter the original column             public class Pair lt T gt                public int Index              public T Value              public Pair int i  T v                    Index   i                  Value   v                                  static IEnumerable lt Pair lt T gt  gt  Iterate lt T gt  this IEnumerable lt T gt  source                int index   0              foreach   var cur in source                    yield return new Pair lt T gt  index cur                   index                                    static void Sort2d string     source  IComparer comp  int col                var colValues   source Iterate                    Select x    new Pair lt string gt  x Index source x Index  col    ToList                colValues Sort  l r     comp Compare l Value  r Value                var temp   new string source 0  Length               var rest   colValues Iterate                while   rest Any                       var pair   rest First                    var cur   pair Value                  var i   pair Index                  if  i    cur Index                         rest   rest Skip 1                       continue                                     Array Copy source i   temp  temp Length                   Array Copy source cur Index   source i   temp Length                   Array Copy temp  source cur Index   temp Length                   rest   rest Skip 1                   rest Where x   gt  x Value Index    i  First   Value Index   cur Index                                   public static void Test1                 var source   new string                                    new string     foo    bar    4                     new string      jack    dog    1                     new string     boy    ball    2                     new string     yellow    green    3                               Sort2d source  StringComparer Ordinal  2

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Can allso look at Array Sort Method http   msdn microsoft com en-us library aa311213 v vs 71  aspx   e g  Array Sort array  delegate object   x  object   y      return  x  i   as IComparable  CompareTo y  i          from http   channel9 msdn com forums Coffeehouse 189171-Sorting-Two-Dimensional-Arrays-in-C

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Array Sort array   a  b       return a 0  - b 0

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If you could get the data as a generic tuple when you read it in or retrieved it  it would be a lot easier  then you would just have to write a Sort function that compares the desired column of the tuple  and you have a single dimension array of tuples

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This is an old question  but here s a class I just built based on the article from Jim Mischel at InformIt linked by Doug L   class Array2DSort   IComparer lt int gt           maintain a reference to the 2-dimensional array being sorted     string     sortArray      int    tagArray      int  sortIndex       protected string    SortArray   get   return  sortArray              constructor initializes the sortArray reference     public Array2DSort string    theArray  int sortIndex                 sortArray   theArray           tagArray   new int  sortArray GetLength 0            for  int i   0  i  lt   sortArray GetLength 0     i   tagArray i    i           sortIndex   sortIndex             public string    ToSortedArray                 Array Sort  tagArray  this           string    result   new string               sortArray GetLength 0    sortArray GetLength 1            for  int i   0  i  lt   sortArray GetLength 0   i                          for  int j   0  j  lt   sortArray GetLength 1   j                                  result i  j     sortArray  tagArray i   j                                   return result                x and y are integer row numbers into the sortArray     public virtual int Compare int x  int y                if   sortIndex  lt  0  return 0          return CompareStrings x  y   sortIndex              protected int CompareStrings int x  int y  int col                return  sortArray x  col  CompareTo  sortArray y  col              Given an unsorted 2D array data of arbitrary size that you want to sort on column 5 you just do this           Array2DSort comparer   new Array2DSort data  5           string    sortedData   comparer ToSortedArray      Note the virtual Compare method and protected SortArray so you can create specialized subclasses that always sort on a particular column or do specialized sorting on multiple columns or whatever you want to do  That s also why CompareStrings is broken out and protected - any subclasses can use it for simple comparisons instead of typing out the full SortArray x  col  CompareTo SortArray y  col   syntax

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Try this out   The basic strategy is to sort the particular column independently and remember the original row of the entry   The rest of the code will cycle through the sorted column data and swap out the rows in the array   The tricky part is remembing to update the original column as the swap portion will effectively alter the original column             public class Pair lt T gt                public int Index              public T Value              public Pair int i  T v                    Index   i                  Value   v                                  static IEnumerable lt Pair lt T gt  gt  Iterate lt T gt  this IEnumerable lt T gt  source                int index   0              foreach   var cur in source                    yield return new Pair lt T gt  index cur                   index                                    static void Sort2d string     source  IComparer comp  int col                var colValues   source Iterate                    Select x    new Pair lt string gt  x Index source x Index  col    ToList                colValues Sort  l r     comp Compare l Value  r Value                var temp   new string source 0  Length               var rest   colValues Iterate                while   rest Any                       var pair   rest First                    var cur   pair Value                  var i   pair Index                  if  i    cur Index                         rest   rest Skip 1                       continue                                     Array Copy source i   temp  temp Length                   Array Copy source cur Index   source i   temp Length                   Array Copy temp  source cur Index   temp Length                   rest   rest Skip 1                   rest Where x   gt  x Value Index    i  First   Value Index   cur Index                                   public static void Test1                 var source   new string                                    new string     foo    bar    4                     new string      jack    dog    1                     new string     boy    ball    2                     new string     yellow    green    3                               Sort2d source  StringComparer Ordinal  2

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Try this out   The basic strategy is to sort the particular column independently and remember the original row of the entry   The rest of the code will cycle through the sorted column data and swap out the rows in the array   The tricky part is remembing to update the original column as the swap portion will effectively alter the original column             public class Pair lt T gt                public int Index              public T Value              public Pair int i  T v                    Index   i                  Value   v                                  static IEnumerable lt Pair lt T gt  gt  Iterate lt T gt  this IEnumerable lt T gt  source                int index   0              foreach   var cur in source                    yield return new Pair lt T gt  index cur                   index                                    static void Sort2d string     source  IComparer comp  int col                var colValues   source Iterate                    Select x    new Pair lt string gt  x Index source x Index  col    ToList                colValues Sort  l r     comp Compare l Value  r Value                var temp   new string source 0  Length               var rest   colValues Iterate                while   rest Any                       var pair   rest First                    var cur   pair Value                  var i   pair Index                  if  i    cur Index                         rest   rest Skip 1                       continue                                     Array Copy source i   temp  temp Length                   Array Copy source cur Index   source i   temp Length                   Array Copy temp  source cur Index   temp Length                   rest   rest Skip 1                   rest Where x   gt  x Value Index    i  First   Value Index   cur Index                                   public static void Test1                 var source   new string                                    new string     foo    bar    4                     new string      jack    dog    1                     new string     boy    ball    2                     new string     yellow    green    3                               Sort2d source  StringComparer Ordinal  2

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Can allso look at Array Sort Method http   msdn microsoft com en-us library aa311213 v vs 71  aspx   e g  Array Sort array  delegate object   x  object   y      return  x  i   as IComparable  CompareTo y  i          from http   channel9 msdn com forums Coffeehouse 189171-Sorting-Two-Dimensional-Arrays-in-C

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This code should do what you are after  I haven t generalised it for n by n  but that is straight forward  That said - I agree with MusiGenesis  using another object that is a little better suited to this  especially if you intend to do any sort of binding    I found the code here   string     array   new string 3      array 0    new string 3     apple    apple    apple     array 1    new string 3     banana    banana    dog     array 2    new string 3     cat    hippo    cat               for  int i   0  i  lt  3  i         Console WriteLine String Format   0   1   2    array i  0   array i  1   array i  2        int j   2   Array Sort array  delegate object   x  object   y          return  x j  as IComparable  CompareTo y  j             for  int i   0  i  lt  3  i        Console WriteLine String Format   0   1   2    array i  0   array i  1   array i  2

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using System  using System Collections Generic  using System Linq  using System Text   namespace ConsoleApplication1       class Program               static void Main string   args                        int    arr       20  9  11      30  5  6                  Console WriteLine  before                for  int i   0  i  lt  arr GetLength 0   i                                  for  int j   0  j  lt  arr GetLength 1   j                                          Console Write   0 3    arr i  j                                      Console WriteLine                              Console WriteLine  After                 for  int i   0  i  lt  arr GetLength 0   i       Array Sorting                               for  int j   arr GetLength 1  - 1  j  gt  0  j--                                         for  int k   0  k  lt  j  k                                                  if  arr i  k   gt  arr i  k   1                                                         int temp   arr i  k                               arr i  k    arr i  k   1                               arr i  k   1    temp                                                                                    Console WriteLine                               for  int i   0  i  lt  arr GetLength 0   i                                  for  int j   0  j  lt  arr GetLength 1   j                                          Console Write   0 3    arr i  j                                      Console WriteLine

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I like the DataTable approach proposed by MusiGenesis above  The nice thing about it is that you can sort by any valid SQL  order by  string that uses column names  e g   x  y desc  z  for  order by x  y desc  z    FWIW  I could not get it to work using column ordinals  e g   3 2 1   for  order by 3 2 1   I used only integers  but clearly you could add mixed type data into the DataTable and sort it any which way   In the example below  I first loaded some unsorted integer data into a tblToBeSorted in Sandbox  not shown   With the table and its data already existing  I load it  unsorted  into a 2D integer array  then to a DataTable  The array of DataRows is the sorted version of DataTable  The example is a little odd in that I load my array from the DB and could have sorted it then  but I just wanted to get an unsorted array into C  to use with the DataTable object   static void Main string   args        SqlConnection cnnX   new SqlConnection  Data Source r90jroughgarden   Initial Catalog Sandbox Integrated Security True        SqlCommand cmdX   new SqlCommand  select   from tblToBeSorted   cnnX       cmdX CommandType   CommandType Text      SqlDataReader rdrX   null      if  cnnX State    ConnectionState Closed  cnnX Open         int    aintSortingArray   new int 100  4         i  elementid  planid  timeid      try                 Load unsorted table data from DB to array         rdrX   cmdX ExecuteReader            if   rdrX HasRows  return           int i   -1          while  rdrX Read    amp  amp  i  lt  100                        i                aintSortingArray i  0    rdrX GetInt32 0               aintSortingArray i  1    rdrX GetInt32 1               aintSortingArray i  2    rdrX GetInt32 2               aintSortingArray i  3    rdrX GetInt32 3                     rdrX Close             DataTable dtblX   new DataTable            dtblX Columns Add  ChangeID            dtblX Columns Add  ElementID            dtblX Columns Add  PlanID            dtblX Columns Add  TimeID            for  int j   0  j  lt  i  j                          DataRow drowX   dtblX NewRow                for  int k   0  k  lt  4  k                                  drowX k    aintSortingArray j  k                             dtblX Rows Add drowX                      DataRow   adrowX   dtblX Select      ElementID  PlanID  TimeID            adrowX   dtblX Select      ElementID desc  PlanID asc  TimeID desc               catch  Exception ex                string strErrMsg   ex Message            finally               if  cnnX State    ConnectionState Open  cnnX Close

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Here is an archived article from Jim Mischel at InformIt that handles sorting for both rectangular and jagged multi-dimensional arrays

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Can I check - do you mean a rectangular array      or a jagged array          It is quite easy to sort a jagged array  I have a discussion on that here  Obviously in this case the Comparison lt T gt  would involve a column instead of sorting by ordinal - but very similar   Sorting a rectangular array is trickier    I d probably be tempted to copy the data out into either a rectangular array or a List lt T   gt   and sort there  then copy back   Here s an example using a jagged array   static void Main         could just as easily be string        int     data   new int                new int    1 2 3            new int    2 3 4            new int    2 4 1               Sort lt int gt  data  2       private static void Sort lt T gt  T     data  int col          Comparer lt T gt  comparer   Comparer lt T gt  Default      Array Sort lt T   gt  data   x y    gt  comparer Compare x col  y col           For working with a rectangular array    well  here is some code to swap between the two on the fly     static T     ToJagged lt T gt  this T    array        int height   array GetLength 0   width   array GetLength 1       T     jagged   new T height          for  int i   0  i  lt  height  i                  T   row   new T width           for  int j   0  j  lt  width  j                          row j    array i  j                     jagged i    row            return jagged    static T    ToRectangular lt T gt  this T     array        int height   array Length  width   array 0  Length      T    rect   new T height  width       for  int i   0  i  lt  height  i                  T   row   array i           for  int j   0  j  lt  width  j                          rect i  j    row j                       return rect       fill an existing rectangular array from a jagged array static void WriteRows lt T gt  this T    array  params T     rows        for  int i   0  i  lt  rows Length  i                  T   row   rows i           for  int j   0  j  lt  row Length  j                          array i  j    row j

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So your array is structured like this  I m gonna talk in pseudocode because my C -fu is weak  but I hope you get the gist of what I m saying   string values rows  columns    So value 1  3  is the value at row 1  column 3   You want to sort by column  so the problem is that your array is off by 90 degrees   As a first cut  could you just rotate it   std  string values by column columns  rows    for  int i   0  i  lt  rows  i      for  int j   0  j  lt  columns  j        values by column column  row    values row  column   sort array values by column column    for  int i   0  i  lt  rows  i      for  int j   0  j  lt  columns  j        values row  column    values by column column  row    If you know you only want to sort one column at a time  you could optimize this a lot by just extracting the data you want to sort     string values to sort rows    for  int i   0  i  lt  rows  i        values to sort i    values i  column to sort     sort array values to sort     for  int i   0  i  lt  rows  i        values i  column to sort    values to sort i    In C   you could play tricks with how to calculate offsets into the array  since you could treat your two-dimensional array as a one-d array  but I m not sure how to do that in c

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Load your two-dimensional string array into an actual DataTable  System Data DataTable   and then use the DataTable object s Select   method to generate a sorted array of DataRow objects  or use a DataView for a similar effect       assumes stringdata row  col  is your 2D string array DataTable dt   new DataTable       assumes first row contains column names  for  int col   0  col  lt  stringdata GetLength 1   col          dt Columns Add stringdata 0  col         load data from string array to data table  for  rowindex   1  rowindex  lt  stringdata GetLength 0   rowindex          DataRow row   dt NewRow        for  int col   0  col  lt  stringdata GetLength 1   col                  row col    stringdata rowindex  col             dt Rows Add row        sort by third column  DataRow   sortedrows   dt Select      3       sort by column name  descending  sortedrows   dt Select      COLUMN3 DESC      You could also write your own method to sort a two-dimensional array   Both approaches would be useful learning experiences  but the DataTable approach would get you started on learning a better way of handling tables of data in a C  application

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If you could get the data as a generic tuple when you read it in or retrieved it  it would be a lot easier  then you would just have to write a Sort function that compares the desired column of the tuple  and you have a single dimension array of tuples

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So your array is structured like this  I m gonna talk in pseudocode because my C -fu is weak  but I hope you get the gist of what I m saying   string values rows  columns    So value 1  3  is the value at row 1  column 3   You want to sort by column  so the problem is that your array is off by 90 degrees   As a first cut  could you just rotate it   std  string values by column columns  rows    for  int i   0  i  lt  rows  i      for  int j   0  j  lt  columns  j        values by column column  row    values row  column   sort array values by column column    for  int i   0  i  lt  rows  i      for  int j   0  j  lt  columns  j        values row  column    values by column column  row    If you know you only want to sort one column at a time  you could optimize this a lot by just extracting the data you want to sort     string values to sort rows    for  int i   0  i  lt  rows  i        values to sort i    values i  column to sort     sort array values to sort     for  int i   0  i  lt  rows  i        values i  column to sort    values to sort i    In C   you could play tricks with how to calculate offsets into the array  since you could treat your two-dimensional array as a one-d array  but I m not sure how to do that in c

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This code should do what you are after  I haven t generalised it for n by n  but that is straight forward  That said - I agree with MusiGenesis  using another object that is a little better suited to this  especially if you intend to do any sort of binding    I found the code here   string     array   new string 3      array 0    new string 3     apple    apple    apple     array 1    new string 3     banana    banana    dog     array 2    new string 3     cat    hippo    cat               for  int i   0  i  lt  3  i         Console WriteLine String Format   0   1   2    array i  0   array i  1   array i  2        int j   2   Array Sort array  delegate object   x  object   y          return  x j  as IComparable  CompareTo y  j             for  int i   0  i  lt  3  i        Console WriteLine String Format   0   1   2    array i  0   array i  1   array i  2

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Can I check - do you mean a rectangular array      or a jagged array          It is quite easy to sort a jagged array  I have a discussion on that here  Obviously in this case the Comparison lt T gt  would involve a column instead of sorting by ordinal - but very similar   Sorting a rectangular array is trickier    I d probably be tempted to copy the data out into either a rectangular array or a List lt T   gt   and sort there  then copy back   Here s an example using a jagged array   static void Main         could just as easily be string        int     data   new int                new int    1 2 3            new int    2 3 4            new int    2 4 1               Sort lt int gt  data  2       private static void Sort lt T gt  T     data  int col          Comparer lt T gt  comparer   Comparer lt T gt  Default      Array Sort lt T   gt  data   x y    gt  comparer Compare x col  y col           For working with a rectangular array    well  here is some code to swap between the two on the fly     static T     ToJagged lt T gt  this T    array        int height   array GetLength 0   width   array GetLength 1       T     jagged   new T height          for  int i   0  i  lt  height  i                  T   row   new T width           for  int j   0  j  lt  width  j                          row j    array i  j                     jagged i    row            return jagged    static T    ToRectangular lt T gt  this T     array        int height   array Length  width   array 0  Length      T    rect   new T height  width       for  int i   0  i  lt  height  i                  T   row   array i           for  int j   0  j  lt  width  j                          rect i  j    row j                       return rect       fill an existing rectangular array from a jagged array static void WriteRows lt T gt  this T    array  params T     rows        for  int i   0  i  lt  rows Length  i                  T   row   rows i           for  int j   0  j  lt  row Length  j                          array i  j    row j

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I know its late but here is my thought you might wanna consider   for example this is array    m m m a a a b b b j j j k l m     and you want to convert it by column number 2  then   string   newArr   new string arr length  for int a 0 a lt arr length a        newArr a    arr a  1    a      create new array that contains index number at the end and also the column values Array Sort newArr   for int a 0 a lt newArr length a          int index   Convert ToInt32 newArr a  newArr a  Length -1          swap whole row with tow at current index     if index    a                string   arr2   arr a           arr a    arr index           arr index    arr2            Congratulations you have sorted the array by desired column  You can edit this to make it work with other data types

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Load your two-dimensional string array into an actual DataTable  System Data DataTable   and then use the DataTable object s Select   method to generate a sorted array of DataRow objects  or use a DataView for a similar effect       assumes stringdata row  col  is your 2D string array DataTable dt   new DataTable       assumes first row contains column names  for  int col   0  col  lt  stringdata GetLength 1   col          dt Columns Add stringdata 0  col         load data from string array to data table  for  rowindex   1  rowindex  lt  stringdata GetLength 0   rowindex          DataRow row   dt NewRow        for  int col   0  col  lt  stringdata GetLength 1   col                  row col    stringdata rowindex  col             dt Rows Add row        sort by third column  DataRow   sortedrows   dt Select      3       sort by column name  descending  sortedrows   dt Select      COLUMN3 DESC      You could also write your own method to sort a two-dimensional array   Both approaches would be useful learning experiences  but the DataTable approach would get you started on learning a better way of handling tables of data in a C  application

[c#] How do I sort a two-dimensional (rectangular) array in C#?

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