Created by David Hager

This array formula returns the number of unique items in a worksheet range.

However, if Rng contains blank cells, this formula returns an error. In this case, use this modified version of the formula.

This array formula returns the Nth largest unique value in a column range.

To apply data validation to a column which allows only unique items to be entered, highlight that column and select Data, Validation from the menu. Choose the custom option and enter the following formula (for column A):

Created by Laurent Longre

This formula counts the number of unique items a column range, only if the cells in the lookup range contain the specified string.

**Editor’s Note:**

rng = A1:A7

colRange = A1:A7

lookupRange = B1:B7

Don’t forget to enter those array formula with Control+Shift+Enter, not just Enter.

Similar to David’s first formula, but I normally use the following to count unique records in a set range:

{=SUM(COUNTIF(RANGE,RANGE)/(COUNTIF(RANGE,RANGE)^2))}

I am new to array programming. Can anyone kindly explain how the following works

I try to figure out myself. However, I always get 1 for ROW(RNG) instead of an array

Why we need MIN(ROW(RNG))+1? I thought MIN(ROW(RNG)) will always be 1

This array formula returns the Nth largest unique value in a column range.

=LARGE(IF(MATCH(Rng,Rng,0)=ROW(Rng)-MIN(ROW(Rng))+1,Rng,””),N)

The formula

=COUNTIF($A$1:A1,A1)=1

works by entering data. If you copy the data from another cell Control+C and paste it Control+V to the Column A (subject to data validation), it will be pasted and data validation will be bypassed!

Question: How to implement proper data validation? Ensuring that either way Data Entering and/or Copy-Pasting will be validated.

Thanks,

Tennor

In the last array formula by Laurent Longre it is worth noting that this formula will only work when there are no blank cells in colrange.

One way around this if you have blank cells at the end of the range is to use ozgrids expanding ranges (http://www.ozgrid.com/Excel/DynamicRanges.htm)

Does anyone know how to make it work if the blank cells are in the middle of the range?

Thanks,

Matt

I am trying to validate a column so that it will send an error alert when 07……..telephone numbers and 09…….. telephone numbers are entered into the column. I am a bit confused about the custom formula to validate this cell. can you help

Natasha: Are 07 and 09 country codes? Can you give some examples of phone numbers that should give the alert?

Natasha,

I assume your trying to catch mobile phone numbers (beginning 07…) and premium rate lines (beginning 09…).

Make sure your phone number column is formatted as text.

Apply the following custom formula in data validation

=AND(LEFT(cell_ref,2)”07?,LEFT(cell_ref,2)”09?)

and add the appropriate warning in your Error Alert.

Brian

Oops! There should be “not equal” signs after the last bracket for each LEFT function. Soz.

Data Validation:

Is it possible to apply the =COUNTIF($H$1:H1,H1)=1 across many worksheets? I have split an asset register across many worksheets and I would like it to check that the serial number does not exist in any worksheet. Is that possible?

Thanks

Paul

Hi

I need help in counting the unqiue records,

Column

Device TypeDevice Model

MFP Canon NP 6050

PrinterHP Color LaserJet 2500N

PrinterHP Color LaserJet 4600n

PrinterHP LaserJet 1010

PrinterHP LaserJet 4000

PrinterHP LaserJet 4050

PrinterHP LaserJet 4100N

PrinterHP LaserJet 4200N

PrinterHP LaserJet 4200N

PrinterHP LaserJet 4200N

PrinterHP LaserJet 4200N

Fax Panasonic AnyModel

MFP Canon NP 6050

PrinterHP Color LaserJet 2500N

PrinterHP Color LaserJet 2550N

PrinterHP Color LaserJet 3700N

this is my data, now i need to if count unique record in cloumn device model where device type is printer.can some one please help me,

Hi Hima : is it that you are tying to count number of times a particular printer has appeared in the list?

=LARGE(IF(MATCH(C7:C15,C7:C15,0)=ROW(C7:C15)-MIN(ROW(C7:C15))+1,C7:C15,””),3)

this didnt work