用VBA简化复杂的excel公式

Question

I have a macro that is generally slow due to overuse of LOOKUP formulas. I want to insert some VBA variables to speed these up. I am currently working on speeding up the formula below:in Excel:

=IF(ISNA(MATCH(A2,Summary!B:B,0)),"n",I2-((I2/LOOKUP(2,1/(I:I<>""),I:I))*VLOOKUP(A2,Summary!$G$10:$H$902,2,FALSE)))

in VBA:

"=IF(ISNA(MATCH(RC[-9],Summary!C[-8],0)),""n"",RC[-1]-((RC[-1]/LOOKUP(2,1/(C[-1]<>""""),C[-1]))*VLOOKUP(RC[-9],Summary!R10C7:R902C8,2,FALSE)))"

The portion I need to replace is LOOKUP(2,1/(C[-1]<>""""),C[-1]) . All this does is reference the last non empty cell in column I. Right now I have the following code to return the address of the last cell in VBA

Sub FormulaTest()
Set lRow = Range("I1").SpecialCells(xlCellTypeLastCell).Address

End Sub

I am trying to figure out how to implement this "lRow" into the VBA code for the formula. Can anyone steer me in the right direction?

**EDIT 1 Please see Fernando's comment below. He has the right idea however the solution is still off a bit. Ill try to explain it better in a few comments: First off, The first row is always a title row, the last row is always a sum row, the current tab is the "Sales" tab, and the amount of rows in any given Sales tab will vary (could be I1:I59, could be I:1:I323).

In this example I1 is a row title and I59 is the sum of I2:I58. Rows I2:I58 are dollar amounts. My macro places this formula in J2:J58. This formula takes each row's dollar amount (I2:I58) as a percentage of the total (I59) and multiplies it by an input amount on the Summary tab (the VLOOKUP). This amount is then subtracted proportionately from the dollar value in column I with the J cell showing the result.

I am looking to eliminate the need for the LOOKUP function (selects last non empty cell) within my formula above: LOOKUP(2,1/(C[-1]<>""""),C[-1]).

**EDIT 2 Fernando's solution worked. Thank you all for your input

Answer 1

This would return the last non-empty row in column I

with Worksheets("Summary")
lRow = .Cells(.Rows.Count, "I").End(xlUp).Row
end with

So your code would be

sub testy
dim lRow as long
with Worksheets("Summary")
lRow = .Cells(.Rows.Count, "I").End(xlUp).Row
end with

"=IF(ISNA(MATCH(RC[-9],Summary!C[-8],0)),""n"",RC[-1]-_
((RC[-1]/R"&lRow&"C[-1])*VLOOKUP(RC[-9],Summary!R10C7:R902C8,2,FALSE)))"

In your solution you're using xlCellTypeLastCell . This is very useful, but it calculates based on UsedRange , which may not be what you want. with this, if you have data up to row n and then you update the data and now you have less records, the last row with xlCellTypeLastCell will still be n , so be careful with that.

Answer 2

Assuming that you are doing all your work on the active sheet, looking up to a "Summary" sheet:

Sub fillCol()

    Dim aRow As Long, bRow As Long

    aRow = Cells(Rows.Count, "I").End(xlUp).Row
    bRow = Sheets("Summary").Cells(Rows.Count, "I").End(xlUp).Row

    Range("J2:J" & aRow).FormulaR1C1 = "=IF(ISNA(MATCH(RC[-9],Summary!C[-8],0)),""n"",RC[-1]-" _
                       & "((RC[-1]/" & aRow & ")*VLOOKUP(RC[-9],Summary!R10C7:R" & bRow & "C8,2,FALSE)))"

End Sub

You made need to change the columns which contain the contiguous range (in order to determine the last row)