vba - loop inside a loop freezes excel - arrays

Question

i am trying to make a loop to go through an array(47193, 4) and an array 2 named attack(41892,1). The idea here is that the attack array has the values in order from the sheet i want to later on add the values to the next column, this is why i add the values to a third array. So the loop is going to go one by one the value from attack array while looping through arr array to find the common data. i tried copying the values directly to the sheet but excel freezes a lot. Now with this way, excel still freezes at this point. Is there anything wrong with it?
Dim arr3() As Variant
Dim dee As Long
ReDim arr3(UBound(attacks, 1), 1)
For k = 0 To UBound(attacks, 1)
j = 0
For j = 0 To UBound(arr, 1)
If attacks(k, 0) = arr(j, 0) And attacks(k, 1) = arr(j, 2) Then
arr3(dee, 0) = attacks(k, 0)
arr3(dee, 1) = attacks(k, 1)
de = dee + 1
End If
Next j
Next k

Answer 1

Here's some code showing how to use a Dictionary:
Sub Tester()
Const SZ As Long = 10000 'size of test arrays
Dim arr1(1 To SZ, 1 To 2)
Dim arr2(1 To SZ, 1 To 2)
Dim arr3(1 To SZ, 1 To 2) '<<matches go here
Dim n As Long, m As Long, i As Long, t, dict, k
t = Timer
'fill test arrays with random data
For n = 1 To SZ
arr1(n, 1) = CLng(Rnd * 200)
arr1(n, 2) = CLng(Rnd * 200)
arr2(n, 1) = CLng(Rnd * 200)
arr2(n, 2) = CLng(Rnd * 200)
Next n
Debug.Print "Filled test arrays", Timer - t
t = Timer
'test the nested loop approach
For n = 1 To SZ
For m = 1 To SZ
If arr1(n, 1) = arr2(m, 1) And arr1(n, 2) = arr2(m, 2) Then
i = i + 1
arr3(i, 1) = arr1(n, 1)
arr3(i, 2) = arr1(n, 2)
End If
Next m
Next n
Debug.Print "Finished nested loop", Timer - t, i & " matches"
t = Timer
'create a lookup using a dictionary
Set dict = CreateObject("scripting.dictionary")
For n = 1 To SZ
k = arr1(n, 1) & "|" & arr1(n, 2)
dict(k) = dict(k) + 1
Next n
Debug.Print "Filled dictionary", Timer - t
t = Timer
i = 0
Erase arr3
'Perform the match against arr2 using the dictionary
For m = 1 To SZ
k = arr2(m, 1) & "|" & arr2(m, 2)
If dict.exists(k) Then
i = i + 1
arr3(i, 1) = arr2(m, 1)
arr3(i, 2) = arr2(m, 2)
End If
Next m
Debug.Print "Finished dictionary loop", Timer - t, i & " matches"
End Sub
Output:
Filled test arrays 0
Finished nested loop 9.101563 2452 matches
Filled dictionary 0.03125
Finished dictionary loop 0.0078125 2177 matches
Note the # of matches is slightly different - the nested loop catches duplicate matches but the Dictionary only counts unique matches. You might need to make adjustments depending on your use case.