Question

I got 2 expandable arrays with strings in them and I want to compare both with each other to see which includes strings that the other dont.

lets say my arrays are like:

ARRAY - 1       ARRAY - 2
   a1               a1
   a2               a2
   a3               a3
   a9               a4
   a10              a8
   a11              a10
   a12              a11

i wanna get the result as:

ARRAY - 4       ARRAY - 5       ARRAY - 6
   a9               a4             a1
   a12              a8             a2
                                   a3
                                   a10
                                   a11

another 3 different array should give me the difference of array1 when compared to array 2

-array4 here gives the strings that is included in array1 but not found in array2
-array5 here gives the strings that is included in array2 but not found in array1
-array6 here gives the strings that is found in both

for this i ve coded:

i = 0
j = 0

For Each innerElement1 In CompareElement1 'CompareElement1 is the array1 here

    NoneFound = 1

    'Ones thats in first element also found in second element..
    For Each innerElement2 In CompareElement2 'CompareElement2 is the array2 here

        If innerElement1 = innerElement2 Then

            'Expand array
            ReDim Preserve IncludedInBoth(0 To UBound(IncludedInBoth) + 1)
            IncludedInBoth(i) = innerElement1
            'Item found in both so NoneFound is 0.
            NoneFound = 0
            i = i + 1

        End If

    Next

    'Ones thats in first element but not found in second element..
    If NoneFound = 1 Then

        'Expand array
        ReDim Preserve NotIncludedInElem2(0 To UBound(NotIncludedInElem2) + 1)
        NotIncludedInElem2(j) = innerElement1
        j = j + 1

    End If

Next

'Seperate Comparison for the ones that found in second element _
 but not found in first element..
i = 0

For Each innerElement1 In CompareElement2

    NoneFound = 1

    'Ones thats in second element also found in first element.
    For Each innerElement2 In IncludedInBoth

        If innerElement1 = innerElement2 Then

            'Item found in both so NoneFound is 0.
            NoneFound = 0

        End If

    Next

    'Ones thats in second element but not found in first element..
    If NoneFound = 1 Then

        'Expand array
        ReDim Preserve NotIncludedInElem1(0 To UBound(NotIncludedInElem1) + 1)
        NotIncludedInElem1(i) = innerElement1
        i = i + 1

    End If

Next

my code up there exactly does the comparing and giving the true answer but with a lack of performance caused by inner for each calls is there a way to do this comparing with a faster way? its taking like forever to finish this comparing..

also a little note:

array1 and array2 are two different sized arrays that contains thousands(~100.000)of strings in each.
also they are not in order. i would like to learn how to order them alphabetically.

Answer 1

with that amount of data, create a database, load to tables and use SQL. It will run too slow trying to do it manually.