MicrosoftSadly, once more I will have to curb my impatience to gain access to these new functions within the beta channel. Hopefully not too long this time!
The functions look manageable from a user perspective and address the concerns I expressed when dynamic arrays first appeared (namely the handling of 2D arrays as an array of 1D arrays and the problem of accumulation being treated as a circular reference - no array breakup). One thing that does concern me is that the order of the parameters in SCAN and REDUCE appears to be illogical. In either case, the main parameter of the function is the array, the initial value represents a minor (optional) adjustment.
A similar situation arose using Charles Williams's ACCUMULATE function
FastExcelV4VS2019 (decisionmodels.com)
in which the function was first implemented as starting with an initial value but was then changed (breaking backward compatibility) to ensure that the flow variable came first in a balance calculation. Starting the parameters list with an omitted initial value gave rise to recurrent user-errors when the function was applied in its original form.
I believe
=SCAN (array, [initial_value], LAMBDA(value, accumulator))
would provide a better signature for the function.
