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I'm trying to search a worksheet for a row where the values in the first 3 columns match a set of 3 criteria. I'm using this linear search:

Function findRow(pName as string,fNo as string,mType as string) As Long Dim rowCtr As Long rowCtr = 2 While Not rowMatchesCriteria(rowCtr, pName,fNo,mType) rowCtr = rowCtr + 1 Wend findRow=rowCtr End Function Function rowMatchesCriteria(row As Long, pName As String, fNo As String, mType As String) As Boolean rowMatchesCriteria = dSheet.Cells(row,1)=pName _ And dSheet.Cells(row,2)=fNo _ And dSheet.Cells(row,3)=mType End Function

We can assume that for any 3 criteria, there is only one match. However, this is very slow. dSheet has ~35,000 entries to search through, and I need to perform ~400,000 searches.

I looked at some of the solutions in this question, and while I'm sure that using AutoFilter or an advanced would be faster than a linear search, I don't understand how to get the index of the row that the filter returns. What I'm looking for would be:

Sub makeUpdate(c1 as string,c2 as string,c3 as string) Dim result as long result = findRow(c1,c2,c3) dSheet.Cells(result,updateColumn) = someUpdateValue End Sub

How do I actually return the result row that I'm looking for once I've applied AutoFilter?

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    look at my answer here: stackoverflow.com/questions/21091948/… Commented May 8, 2014 at 19:35
  • 1
    @simoco, the SpecialCells(xlCellTypeVisible) is what I was thinking of. Thanks for the link. Commented May 8, 2014 at 20:31

4 Answers 4

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For performance you're hard-pressed to beat a Dictionary-based lookup table:

Sub FindMatches() Dim d As Object, rw As Range, k, t Dim arr, arrOut, nR, n t = Timer 'create the row map (40k rows) Set d = GetRowLookup(Sheets("Sheet1").Range("A2:C40001")) Debug.Print Timer - t, "map" t = Timer 'run lookups on the row map '(same values I used to create the map, but randomly-sorted) For Each rw In Sheets("sheet2").Range("A2:C480000").Rows k = GetKey(rw) If d.exists(k) Then rw.Cells(3).Offset(0, 1).Value = d(k) Next rw Debug.Print Timer - t, "slow version" t = Timer 'run lookups again - faster version arr = Sheets("sheet2").Range("A2:C480000").Value nR = UBound(arr, 1) ReDim arrOut(1 To nR, 1 To 1) For n = 1 To nR k = arr(n, 1) & Chr(0) & arr(n, 2) & Chr(0) & arr(n, 3) If d.exists(k) Then arrOut(n, 1) = d(k) Next n Sheets("sheet2").Range("D2").Resize(nR, 1).Value = arrOut Debug.Print Timer - t, "fast version" End Sub 'create a dictionary lookup based on three column values Function GetRowLookup(rng As Range) Dim d As Object, k, rw As Range Set d = CreateObject("scripting.dictionary") For Each rw In rng.Rows k = GetKey(rw) d.Add k, rw.Cells(1).Row 'not checking for duplicates! Next rw Set GetRowLookup = d End Function 'create a key from a given row Function GetKey(rw As Range) GetKey = rw.Cells(1).Value & Chr(0) & rw.Cells(2).Value & _ Chr(0) & rw.Cells(3).Value End Function
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If you want to do an exact lookup on 3 columns, you can use VLOOKUP using a slight trick: you create a key based on your 3 columns. E.g. if you want to perform your query on columns B, C, D, create a key column in A based on your three columns (e.g. =B1&C1&D1). Then: 

=VLOOKUP(lookupvalue1&lookupvalue2&lookupvalue3,A:D,{2,3,4},FALSE)

should do the magic.

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One simple solution could be using excel function MATCH as array formula. No for-each loops so I guess this could run very fast.

Formula will look e.g. like this MATCH("A"&"B"&"C",RANGE_1&RANGE_2&RANGE_3,0)

Option Explicit Private Const FORMULA_TEMPLATE As String = _ "=MATCH(""CRITERIA_1""&""CRITERIA_2""&""CRITERIA_3"",RANGE_1&RANGE_2&RANGE_3,MATCH_TYPE)" Private Const EXACT_MATCH = 0 Sub test() Dim result result = findRow("A", "B", "C") Debug.Print "A,B,C was found on row : [" & result & "]" End Sub Function findRow(pName As String, fNo As String, mType As String) As Long On Error GoTo Err_Handler Dim originalReferenceStyle originalReferenceStyle = Application.ReferenceStyle Application.ReferenceStyle = xlR1C1 Dim data As Range Set data = ActiveSheet.UsedRange Dim formula As String ' Add criteria formula = Replace(FORMULA_TEMPLATE, "CRITERIA_1", pName) formula = Replace(formula, "CRITERIA_2", fNo) formula = Replace(formula, "CRITERIA_3", mType) ' Add ranges where search formula = Replace(formula, "RANGE_1", data.Columns(1).Address(ReferenceStyle:=xlR1C1)) formula = Replace(formula, "RANGE_2", data.Columns(2).Address(ReferenceStyle:=xlR1C1)) formula = Replace(formula, "RANGE_3", data.Columns(3).Address(ReferenceStyle:=xlR1C1)) ' Add match type formula = Replace(formula, "MATCH_TYPE", EXACT_MATCH) ' Get formula result findRow = Application.Evaluate(formula) Err_Handler: ' Set reference style back Application.ReferenceStyle = originalReferenceStyle End Function

Output: A,B,C was found on row : [4]

Data:

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In order to improve the best answer (multi criteria search), you would want to check for duplicates to avoid error.

'create a dictionary lookup based on three column values Function GetRowLookup(rng As Range) Dim d As Object, k, rw As Range Set d = CreateObject("scripting.dictionary") For Each rw In rng.Rows k = GetKey(rw) if not d.exists(k) then d.Add k, rw.Cells(1).Row 'checking for duplicates! end if Next rw Set GetRowLookup = d End Function
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