Help understand LAMBDA function

Hi Team,

Can you help me understanding how "r" came in to existence in LAMBDA function in below post #9 by TMS

How it works and what calculation assigned to "r"

https://www.excelforum.com/excel-for...a-instead.html

The formula is this:

=LET(b,B8:B190,c,C8:C190,u,UNIQUE(b),HSTACK(u,BYROW(u,LAMBDA(r,SUMPRODUCT((b=r)*(c))))))

r is a parameter - it refers back to the parameter u, which is UNIQUE(B8:B190) and returns one row of that at a time.

If you are using LAMBDA, then your forum profile is out-of-date - please update it.

The syntax is this:

BYROW(array,LAMBDA(parameter_for_array,calculation))

On this occasion, r is often used as it reminds us that the array will be called ROW by ROW, but you could use any letter that hasn't already been used as a parameter and that will be referenced in the LAMBDA caclulation.

It will become apparent the more that you use it yourself.

Your profile shoul show ONLY the OLDEST version of Excel that any solution offered to you must work for. Thanks.

It does, but there are still TWO versions there - see the last line of my previous post and update it again, please.

Glad to have helped.

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Thank you.