Iferror

I just wondered what people's opinions were on the use of the IFERROR function. Pre 2007 I often used to warn people off widely using ISERROR as it can mask all kinds of problems and make workbooks quite hard to find problems in.

I'm by no means saying that neither have their place and the greater simplicity of IFERROR over having to repeat your functions within an IF statement is welcome. I just think it could become overused when problems can be fixed further up the calculation chain.

Dom

I think that many factors come into play when deciding on the use of IFERROR.

What is the purpose of the sheet? If the sheet is used as display/reporting only, then IFERROR is nice because it will display a more friendly message (or often no message) when an error occurs, rather than #N/A or whatever. If the sheet, however, is used for production and calculation on data, then leave the errors alone and resolve them at the source, if possible.

When using IFERROR, follow the same rule as variable scope. Use the smallest "Scope" as possible. Don't just wrap your entire formula in an IFERROR function. Only use it on the parts that will actually return an error.
For example: "=IFERROR(B7/G13,0)*M13", or "=IFERROR(Vlookup("Test",A:B,2,False),0) * C1"

I try to take the same approach as error handling in VBA. It is necessary because errors will cause issues and frustration for the user, and you need to handle those errors and return a useful message to the user, or do a different calculation. But just as using On Error Resume Next in every sub or function is to be avoided, over using IFERROR is a bad practice.

It is just another tool to use to get the job done. If the tool is not appropriate for the job, don't use it. It is like Duct Tape. Yes, it fixes a lot of things, but sometimes it is just a band-aid fix, is ugly, and some glue or a screwdriver is a better choice.

I don't always use Duct Tape. Sometimes I reach for the No More Nails

Dom

I actually didn't notice there was an iferror until about a week ago.
Is Iferror() that much easier than If(iserror())?

Can we please get an Ifsum() function too? How about IfVlookup()?

Maybe there is a subtle difference I'm not aware of.

It just means you can write:

=IFERROR(VLOOKUP(blah blah),"")

Rather than:

=IF(ISERROR(VLOOKUP(blah blah)),"",VLOOKUP(blah blah))

I don't know if it's more efficient but is simpler to write. I've also noticed more people using it as it's mentioned as a nice new function.

Dom

Originally Posted by Whizbang

It is more efficient because it only calculates the VLOOKUP(blah blah)) part once.

Logically that would be the case. Will check out that thread,

Cheers,

Dom