data validation for a single text entry

[MZ]

How can I create a data validation for a single text entry (i.e. to allow
leaving the cell blank or entering the word "Yes") without having to create a
list of the single entry (i.e. Yes). The other options in data validation
related to numbers, not text.
Thank you

 

[Eduardo]

Hi,
I assume I enter the word Yes in cell B1 then position in the cell you want
to apply data validation, go to data validation, custom and enter there the
formula as follow

=OR(A1=B1,A1="")

the above formula is validating data entered in A1

 

[cm]

Assuming your input cell is F10, In the data validation box -- choose Custom
and in the formula box put:

=OR(ISBLANK(F10)=TRUE,F10="Yes")

 

[T. Valko]

Assume you want to allow only the entry Yes in cell A1 (or leave it empty).

Select cell A1
Goto the menu Data>Validation
Allow: Custom
Formula: =A1="yes"
OK

 

[MZ]

Thank you T. Valko,
I tried your suggestions and typed: =AF="Yes" (AF is the cell address)
but received a pop-up error in the Validation box that states: A named range
you specified cannot be found

 

[T. Valko]

I tried your suggestions and typed: =AF="Yes"

(AF is the cell address)

Ok, so what's the row number of the cell address? Is it AF10? AF25? You need
to include the row number.

 

[MZ]

Thank you for correcting my error in identifying the cell; it works fine now

 

[T. Valko]

Good deal. Thanks for the feedback!

 

[Debra Dalgleish]

Another option is to select Allow: List
In the Source box, type: Yes
Remove the check mark from the box for In-cell drop down

Note: Entries will have to exactly match what you type in the Source
box, so YES or yes would not be allowed, only Yes

If you want to allow other variations, you could add them in the Source
Box, e.g.: Yes,YES,yes