Difference in Arrays

Question

If I have an array (1,2,3,4,5,6,7,8) and another array (2,4,6)

How do I get a third array (1,3,5,7,8)?

I can't use LINQ, I'm working on .NET CF 2.0. How can I do this without using LINQ or is there a LINQ resource compatible with .NET CF 2.0?

[Linq on the .NET 2.0 Runtime](http://stackoverflow.com/questions/2138/linq-on-the-net-2-0-runtime) — mggSoft, Nov 07 '14 at 10:43
You can use nested for loop. Compare the values, end exclude the equal ones. — vortex, Nov 07 '14 at 10:45

score 2 · Answer 1 · answered Nov 07 '14 at 10:53

For each element of the first array you check whether the second array contains it. If it doesn't then you add it to the result:

var array1 = new[] { 1,2,3,4,5,6,7,8 };
var array2 = new[] { 2,4,6 };

var result = new List<int>();

foreach (var value1 in array1)
{
    bool exists = false;

    foreach (var value2 in array2)
    {
        if (value1 == value2)
        {
            exists = true;
            break;
        }
    }

    if (!exists)
    {
        result.Add(value1);
    }
}

// result is { 1,3,5,7,8 }

Callum Linington · Answer 2 · 2014-11-07T10:57:43.263

1

var intList = new List<int>();
for (var i = 0; i < mainArray.Length; i++) // loop through the first array
{
    var exists = false;

    for (var y = 0; y < otherArray.Length; y++) // loop through the next array
    {
        if (mainArray[i] != otherArray[y]) // if the values arent equal
        {
            exists = true;
            break;
        }
    }

    if (!exists)
    {
        intList.Add(mainArray[i]); // put them in the new list
    }
}

Here is the foreach method:

foreach (var main in mainArray)
{
    foreach (var other in otherArray)
    {
         // same logic as above
    }
}

edited Nov 07 '14 at 10:57

answered Nov 07 '14 at 10:44

Callum Linington

14,213
12
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Logic is fundamentally flawed. Just run with a sample data and test yourself. – Sriram Sakthivel Nov 07 '14 at 10:53
Example: `main` item `2`. First `other` item is also `2`, so you don't add it to `intList`. But then you go to the second `other` item `4`. Now `2 != 4` and you add `2`. – Corak Nov 07 '14 at 10:54
Yeah just saw the other answer. – Callum Linington Nov 07 '14 at 10:55

score 1 · Answer 3 · answered Nov 07 '14 at 10:45

1

LINQ is only a simplified way of looping through elements in an enumerable.

Follow this pseudo code:

declare result
foreach item in array1
   if array2 does not contain item
      add item to result

answered Nov 07 '14 at 10:45

jaypeagi

3,133
18
33

Thariq Nugrohotomo · Accepted Answer · 2014-11-07T23:27:41.217

1

hope this will be the shortest answer :)

int[] arr1 = new int[] { 1, 2, 3, 4, 5, 6, 7, 8 };
int[] arr2 = new int[] { 2, 4, 6 };

// copy the content of arr1 into a temporary List
List<int> temp = new List<int>(arr1);
// kick-out unneeded elements from temporary List
foreach (int toRemove in arr2) temp.Remove(toRemove);

// it's done
int[] result = temp.ToArray();

edited Nov 07 '14 at 23:27

answered Nov 07 '14 at 10:58

Thariq Nugrohotomo

733
1
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Thats nice! I like it! Can be a bit hard to read, but ... just add comments ennit! – Callum Linington Nov 07 '14 at 11:00
@No1_Melman I like this one, especially as it is so short. But I can't use `var` either. Yeah I know, it sucks. But I'm developing for a somewhat old handheld device and that is the main issue. – manlikeangus Nov 07 '14 at 11:06
I have updated my answer again. I forget that .NET CF 2.0 still don't have var statement. – Thariq Nugrohotomo Nov 07 '14 at 11:09
@ThisUser `var` isn't a big issue, just replace with the type. – Callum Linington Nov 07 '14 at 11:20

Difference in Arrays

4 Answers4