[Jprogramming] Evolution of a J code

[Miller, Raul D]

Oleg Kobchenko wrote:
> for (i ...) {
>   a[i] = a[i] > 0.5 ? 1 : -1;
> }
> 
> or even
> 
> for (i ...) {
>   a[i] = 1 + -(int)(a[i] > 0.5);
> }

Note that these two "a" arrays seem to be different after
the loop.

The first loop modifies the array so that it contains
the values 1 or -1.

The second loop modifies the array so that it contains
the values 1 or 0, and is roughly equivalent to the
J expression a <: 0.5

As an aside, I find that unnecessary steps in a program 
tend to make that program hard to understand (and 
hard to understand programs tend to contain hidden
errors).

-- 
Raul