Create and indexing a matrix simultaneously

Hello,

I'm trying to create an index a matrix in one line. There are a lot of examples I could use, but if I want the second element I would like to write something like:

a=ismember(eye(3),0)(2)

or even just

a=eye(3)(2)

The error I always run in to is this:

??? Error: ()-indexing must appear last in an index expression.

Any help is greatly appreciated!

Answer 1

[Walter Roberson]

a = subsref(ismember(eye(3),0),struct('type','()','subs',2))

[Sarah Berurer]

Walter, this is excellent, exactly the kind of thing I'm looking for. I've been playing around with this for a while, but I keep getting the error "??? Error using ==> subsref

The "subs" field for the subscript argument to SUBSREF and SUBSASGN must be a cell or character array." Any ideas how to fix this?

[Walter Roberson]

Try

a = subsref(ismember(eye(3),0),struct('type',{'()'},'subs',{{2}}))

[Sarah Berurer]

Awesome thank you!

Answer 2

[Jan]

 An anchor drifts along
 Green and red circling endlessly
 A fallen MATLAB feature

http://www.mathworks.com/matlabcentral/answers/1325-what-is-missing-from-matlab#answer_1931

[Jan]

Daniel & Cyclist: You have been faster! But I have the direct link to Walters suggestion ;-)

[Daniel Shub]

and now I do too :)

The power of editing.

[Jan]

I have the editor power - I can even *remove* the anchor from your answer again! (Is there an emoticon for a sardonic grinning?)

[Jan]

Nice! I actually wanted to delete this useless answer. But suddenly it became art. The power will be with us.

Answer 3

[Daniel Shub]

You cannot do it.

See: http://www.mathworks.com/matlabcentral/answers/1325-what-is-missing-from-matlab#answer_1931

Answer 4

[the cyclist]

That sort of indexing is not possible. See for example, the accepted answer here:

http://www.mathworks.com/matlabcentral/answers/1325-what-is-missing-from-matlab