Merge or concatenate column by adjacent cell value - vba

Question

Is it possible to concatenate cells in a column dependent on values (ID) in another column, and then output as a string (possibly in another sheet as it would be cleaner)?
E.g.
ID Text
1234 a
1234 b
1234 c
4321 a
4321 b
4321 c
4321 d
Output:
1234 a b c
4321 a b c d
Issues:
Column IDs aren't in order (but can be sorted).
Different amounts of each ID
This seemed like a possible VBA solution
from How to merge rows in a column into one cell in excel?
Function JoinXL(arr As Variant, Optional delimiter As String = " ")
'arr must be a one-dimensional array.
JoinXL = Join(arr, delimiter)
End Function
Example usage:
=JoinXL(TRANSPOSE(A1:A4)," ")
So I thought maybe if INDEX and MATCH etc could be used in conjuction with TRANSPOSE it could work. Just not sure how to go about it.
I can have a column of the unique IDs in another sheet.

Answer 1

This solution is nice because it works even in cases where:
The text you're concatenating contains spaces.
You want to use a delimiter other than a space (ie a comma).
First, add "Transpose" to your custom function
Function JoinXL(arr As Variant, Optional delimiter As String = " ")
'arr must be a one-dimensional array.
arr = Application.Transpose(arr)
JoinXL = Join(arr, delimiter)
End Function
For vertical arrays, use this formula (replace comma+space with your delimiter of choice, and "{}" with your garbage characters of choice):
{=SUBSTITUTE(SUBSTITUTE(JoinXL(IF($A$2:$A$31=D3,$B$2:$B$31,"{}"),", "),"{}, ",""),", {}", "")}
For horizontal arrays, use this formula:
{=SUBSTITUTE(SUBSTITUTE(JoinXL(IF(TRANSPOSE($E$19:$AH$19)=D12,TRANSPOSE($E$20:$AH$20),"{}"),", "),"{}, ",""),", {}", "")}
Make sure you enter the formulas as array formulas (Ctrl+Shift+Enter after typing formula in cell).

Answer 2

While no convenient function like your cited example, consider using a dictionary of collections with the ID column as the key. Below macro assumes data begins at A2 (column headers in first row) with result outputting in D and E columns:
Sub TransposeValuesByID()
Dim i As Integer, lastrow As Integer
Dim valDict As Object
Dim innerColl As New Collection
Dim k As Variant, v As Variant
Set valDict = CreateObject("Scripting.Dictionary")
lastrow = Cells(Rows.Count, "A").End(xlUp).Row
For i = 2 To lastrow
If Range("A" & i) = Range("A" & i + 1) Then
innerColl.Add Range("B" & i)
Else
innerColl.Add Range("B" & i)
valDict.Add CStr(Range("A" & i).Value), innerColl
Set innerColl = Nothing
End If
Next i
i = 2
For Each k In valDict.keys
Range("D" & i) = k
For Each v In valDict(k)
Range("E" & i) = Trim(Range("E" & i) & " " & v)
Next v
i = i + 1
Next k
End Sub

Answer 3

Since all you want is space between you can use your code with a couple changes.
If your data is Vertical you need to transpose the array to make it a one dimensional array:
Function JoinXL(arr As Variant, Optional delimiter As String = " ")
'arr must be a one-dimensional array.
arr = Application.Transpose(arr)
JoinXL = Join(arr, delimiter)
End Function
If it is horizontal then use what you have.
The main change is how you call it.
Use the following array formula:
=TRIM(JoinXL(IF($A$2:$A$8=C2,$B$2:$B$8,"")," "))
being an array it needs to be confirmed with Ctrl-Shift-Enter instead of Enter when exiting edit mode. If done correctly then Excel will put {} around the formula.
The If passes an array of values or blanks depending on if the cell is equal to the criteria.
Put this in the first cell Hit Ctrl-Shift-Enter. Then drag/copy down

Answer 4

I've come up with a work around, that although a little cumbersome works quite nicely.
Table has to be sorted by ID.
In another sheet.
ID: (Column A)
1234
MIN REF: (Column B)
=ADDRESS(MATCH(A2,OCCRANGE,0)+1,6)
MAX REF: (Column C)
=ADDRESS(MATCH(A2,OCCRANGE)+1,6)
RANGE: (Column D)
=CONCATENATE("'OCCS COMBINED'!",B2,":",C2)
STRING: (Column E)
{=IF([#[MIN REF]]=[#[MAX REF]],INDIRECT(CONCATENATE("'OCCS COMBINED'!",[#[MIN REF]])),JoinXL(TRANSPOSE(INDIRECT(D2)), " "))}