Allow users to define custom non-VBA functions from built in functions, this can be used to simplify complex functions that are used often e.g.
FastVlookup = (X, Y, Z) => IF(VLOOKUP(X,Y,1,TRUE)=X,VLOOKUP(X,Y,Z,TRUE),NA())
Good news! We have added support for native lambdas as of today in Insiders: Beta.
Please see this post for more details:
Was this idea posted by Ryan Hoover from Product Hunt or someone with the same name?
Chris Gross [MSFT] commented
Hello, I wanted to say that we have added support for native lambdas as of today in Insiders: Beta.
Steven Soeder commented
You can create a named function already. Just create your function in a cell, highlight the text in the formula bar, and copy it. Then, goto the formulas tab and open Name Manager, press "New..." and paste your formula into the "Refers to" field. Press the green checkmark to save.
Note: if you use relative cell references, they will remain relative - similar to how conditional formatting works.
See screenshot for example.
Kenneth Barber commented
Not sure what is so "lambda function" about this if you pretty much have to assign the anonymous function a name.
Also, I already have a similar idea posted. Hopefully an Excel UserVoice admin will combine the two.