Initialization of loop index when loop is not entered

I notice that loop indices are initialized to empty double even when the loop is not entered. Is this undocumented behavior or something that is a stable feature that we can depend on in our code? (Matlab 2016a)

>> clear
>> for k=1:0;end
>> whos
  Name      Size            Bytes  Class     Attributes

    k         0x0                 0  double

Answer 1

[Star Strider]

The colon operator by defauklt increments by 1 unless you tell it to increment by a different positive or negative step.

In:

k = 1:0

the loop is ‘satisfied’ at the outset, so no increment takes place and ‘k’ is empty. I can’t find that in a brief scan of the documentation on colon,: (link). It could be documented elsewhere.