use logical indexing to access multiple lines syntax

Still a noob, I try to make my questions coherent... glad to learn

I have a multi-column matrix p552r1_tnL (14918x44 double)

In the second column, I want to find the highest values, so I did this...

 >> p = (p552r1_tnL(:,2))>0.85*max(p552r1_tnL(:,2));
>> sum(p)

% sum(p) is 40 so getting the highest 40 values is a good start... so that gets my matrix way down,

now I just want to get the values in the first three columns of p552r1 based on that logical matrix... I can get it to give me a single column, but can't work out how to get multiple...

     p552r1kmeans = p552r1_tnL(p);  %ok, so it gets me one column

So I've tried

p552r1kmeans (:,1:3)= p552r1_tnL(p);  %Error: matrix sides don't match

p552r1kmeans (:,1:3)= p552r1_tnL(:,1:3)(p); %Error: ()-indexing must appear last in an indexing expression, which I don't get since (p) is last

Thank you for the help : )

Answer 1

[Fangjun Jiang]

temp=p552r1_tnL(p,1:3)

[Hew McKean]

Thank you!

Answer 2

[Dennis]

Almost there ;) in p you have the row positions:

p552r1kmeans=p552r1_tnL(p,1:3)

[Hew McKean]

Thank you : )