Array find and sort

  • Thread starter Thread starter Arjen
  • Start date Start date
A

Arjen

Hi,

I need to add this inside an array:
1 3
2 4
3 2
4 5
5 1

I think of using this:
Int32[,] myValues;

Now I want to find a value (index) in the first colomn. Let's say I'm
looking for value 3, the find result will be 3.
After that I want to sort the array bases on the values in column two.

How can I do that?

Thanks!
 
Whoops...

"...result will be 3." must be "...result will be 2."

And "...array bases on..." should be "...array based on..."
 
Arjen said:
Whoops...

"...result will be 3." must be "...result will be 2."

And "...array bases on..." should be "...array based on..."
Click to expand...

You are looking for a map implementation. There are lots of them. A
simplistic approach might be...

public class Map
{
public int _key;
public int _val;

public Map(int key, int val)
{
_key = key;
_val = val;
}

public bool Match( int val )
{
return _key == val;
}
}

// Then to add and search...
ArrayList al = new ArrayList();
al.Add( new Map(1,3) );
al.Add( new Map(2,4) );
al.Add( new Map(3,2) );

// Find an entry for 3.
int retVal = -1;
for ( int i=0; i<al.Count; ++i )
{
Map m = (Map)al;
if ( m.Match( 3 ) )
{
retVal = m._val;
break;
}
}
 
What you want to do is use a Hashtable to store a key value.

I didnt test it.
But I don't see why it shouldn't work.

public struct KeyValue
{
public KeyValue(int key, int value)
{
Key = key;
Value = value;
}

public int Key;
public int Value;
}

public class MyComparer : IComparer
{
int IComparer.Compare(Object x, Object y)
{
KeyValue keyValueLeft = (KeyValue) x;
KeyValue keyValueRight = (KeyValue) y;
return((new CaseInsensitiveComparer()).Compare(keyValueRight.Value,
keyValueLeft.Value));
}
}

public void test()
{
ArrayList array = new ArrayList();
array.Add(new KeyValue(1,3));
array.Add(new KeyValue(2,4));
array.Add(new KeyValue(3,2));
array.Add(new KeyValue(4,5));
array.Add(new KeyValue(5,1));
array.Sort(new MyComparer());

Hashtable table = new Hashtable();
foreach(KeyValue keyValue in array)
table.Add(keyValue.Key, keyValue.Value);

//Here we look for keys....
Console.WriteLine(table[3]); // the return object is "2";

//The hastable was already loaded with sorted Key Values by the second
colum.
foreach(int i in table.Keys)
Console.WriteLine("Key:" + i + " Value:" + table);

//It should shows
//Key: 5 Value: 1
//Key: 3 Value: 2
//Key: 1 Value: 3
//Key: 2 Value: 4
//Key: 4 Value: 5
}

Gustavo.
 
this is a more elegant solution:

try this and let me know if it works.

public class MyComparer2 : IComparer
{
private SortedList mSortedList;

public SortedList SortedList
{
get{return mSortedList;}
set{mSortedList = value;}
}

int IComparer.Compare(Object x, Object y)
{
int keyLeft = (int) x;
int keyRight = (int) y;
return((new CaseInsensitiveComparer()).Compare(mSortedList[y],
mSortedList[x]));
}
}

public void test()
{
MyComparer2 comparer = new MyComparer2();
SortedList sortedList = new SortedList(comparer);
comparer.SortedList = sortedList;

sortedList.Add(1,3);
sortedList.Add(2,4);
sortedList.Add(3,2);
sortedList.Add(4,5);
sortedList.Add(5,1);

//Here we look for keys....
Console.WriteLine(sortedList[3]); // the return object is "2";

//The SortedList was dinamically sorted by the second column when the items
are loaded.
foreach(int i in sortedList.Keys)
Console.WriteLine("Index:" + sortedList.IndexOfKey(i) + " Key:" + i + "
Value:" + sortedList);

//It should shows
//Index:1 Key: 5 Value: 1
//Index:2 Key: 3 Value: 2
//Index:3 Key: 1 Value: 3
//Index:4 Key: 2 Value: 4
//Index:5 Key: 4 Value: 5
}

Gustavo

What you want to do is use a Hashtable to store a key value.

I didnt test it.
But I don't see why it shouldn't work.

public struct KeyValue
{
public KeyValue(int key, int value)
{
Key = key;
Value = value;
}

public int Key;
public int Value;
}

public class MyComparer : IComparer
{
int IComparer.Compare(Object x, Object y)
{
KeyValue keyValueLeft = (KeyValue) x;
KeyValue keyValueRight = (KeyValue) y;
return((new CaseInsensitiveComparer()).Compare(keyValueRight.Value,
keyValueLeft.Value));
}
}

public void test()
{
ArrayList array = new ArrayList();
array.Add(new KeyValue(1,3));
array.Add(new KeyValue(2,4));
array.Add(new KeyValue(3,2));
array.Add(new KeyValue(4,5));
array.Add(new KeyValue(5,1));
array.Sort(new MyComparer());

Hashtable table = new Hashtable();
foreach(KeyValue keyValue in array)
table.Add(keyValue.Key, keyValue.Value);

//Here we look for keys....
Console.WriteLine(table[3]); // the return object is "2";

//The hastable was already loaded with sorted Key Values by the second
colum.
foreach(int i in table.Keys)
Console.WriteLine("Key:" + i + " Value:" + table);

//It should shows
//Key: 5 Value: 1
//Key: 3 Value: 2
//Key: 1 Value: 3
//Key: 2 Value: 4
//Key: 4 Value: 5
}

Gustavo.

Arjen said:
Hi,

I need to add this inside an array:
1 3
2 4
3 2
4 5
5 1

I think of using this:
Int32[,] myValues;

Now I want to find a value (index) in the first colomn. Let's say I'm
looking for value 3, the find result will be 3.
After that I want to sort the array bases on the values in column two.

How can I do that?

Thanks!
Click to expand...
Click to expand...
 
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