'is there a better way to express "column 5-6"'
Yes.
You can use all(). Specifically, all(~isnan(__),2) where the 2 tells all() to operate over the columns (2nd dimension). ("All are non-NaN.")
Or you can use any(). Specifically, ~any(isnan(__),2). ("Not any are NaN.")
M = [1 50 60 70 50 40
2 NaN 10 20 10 10
3 NaN 20 NaN NaN NaN
1 NaN 60 30 40 50
2 10 20 10 20 NaN
1 30 20 40 NaN 50
2 NaN 50 50 1 NaN];
These three are equivalent:
P = isnan(M(:,2)) & ~isnan(M(:,5)) & ~isnan(M(:,6))
P = isnan(M(:,2)) & all(~isnan(M(:,[5 6])),2)
P = isnan(M(:,2)) & ~any(isnan(M(:,[5 6])),2)
Note that I'm using ~isnan() where you used isfinite(). The difference is how Inf and -Inf are treated.
~isnan(Inf)
isfinite(Inf)
And since the rules you describe talk about NaN vs non-NaN and say nothing about finte vs infinite, I think it makes sense to use isnan and ~isnan.
