How to avoid for loop when indexing?

Hello,

I have the following for loop, where pairs(500x10), is there to calculate cc without for loop?

   for i=1:500
cc(i,:)=pairs(i,pairs(i,:));
end

[Stephen23]

@Mantas Vaitonis: what is pairs2 ? What values do pair and pairs2 contain?

[Mantas Vaitonis]

Sorry, tehre was mistake, both are pairs, they contain double type values like [1 5 4 3 5].

[Stephen23]

@Mantas Vaitonis: given that pairs contains non-integer values, what do you expect

pairs(i,pairs(i,:));

to do?

[Mantas Vaitonis]

Those values suppose to be integer, i fixed my commnet, and should return valuse by index stored in pairs.

Answer 1

[Jan]

s     = size(pairs);
index = sub2ind(s, repmat((1:s(1)).', 1, s(2)), pairs) 
cc    = pairs(index)

[Mantas Vaitonis]

Unfortunately, it is not what I am looking for. With Your code if I have pairs [5 1 4 5 1], cc should be [1 5 5 1 5] and the result with your code is [4 5 2 4 5].

[Jan]

pairs = [5 1 4 5 1];
s     = size(pairs);
index = sub2ind(s, repmat((1:s(1)).', 1, s(2)), pairs) 
cc    = pairs(index)

cc =
     1 5 5 1 5

I don't know why you get [4 5 2 4 5]. Please try it again.

[Mantas Vaitonis]

Maybe I did mistake when copying your code, now it did work, thank you.