REDUCE and VSTACK

[sadath]

Hi,

can anyone explain how the formula work
=REDUCE("",{1,2,3,4},LAMBDA(a,b,VSTACK("",a&" "&b)))

I am getting result
4
3 4
2 3 4
1 2 3 4


if b is each value in the array, then the result should be
1
1 2
1 2 3
1 2 3 4

 

[hagia_sofia]

Hello, REDUCE returns the final outcome of the calculation. So, simple

REDUCE("",{1,2,3,4},LAMBDA(a,b,b))

returns the last value of the array which is 4.