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Indexing of fresh array in one line without intermediate variable.

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Maxim
Maxim on 6 Jun 2013
Commented: Walter Roberson on 6 Feb 2020
How do I index a newly made array without intermediate variables?
Maybe not the best example, but imagine I want to do this
regexp(string,expression,'match')(10:20)
How do I do it in one line?
It is not a regexp question. This problem occurs in many different situations. Thank you
EDIT Another example
function ans = Func(array)
array
end
I want it to look like
Func(1:10)(2:3)
But I need to do
temporary = Func(1:10);
temporary(2:3)

  3 Comments

UniqueWorldline
UniqueWorldline on 14 Nov 2017
For anyone finding this question as late as I have, but who is looking for a simple solution for the
size
function, do the following to only get the one index of the array size you are looking for:
A = [1,2,3,4,5]; % Some array
arrayCols = size(A); % This returns a 1x2 array with the number of rows
% and columns of A. Which is undesirable if only
% the columns are wanted. Instead do this:
[arrayRows,arrayCols] = size(A);
Now arrayCols is a scalar value that can be used immediately. This doesn't allow you to do
size(A)(2)
but it can still eliminate an intermediate.

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Accepted Answer

Maxim
Maxim on 6 Jun 2013
Edited: Maxim on 6 Jun 2013
Problem
magic(5)(3)
Solution 1
value = subsref(magic(5),struct('type','()','subs',{{3,3}}));
Solution 2
paren = @(x, varargin) x(varargin{:});
paren(magic(5), 3, 3);

  2 Comments

Jose Daniel Ortiz
Jose Daniel Ortiz on 18 Sep 2018
So, basically, Matlab does not really support execution and indexing in the same line. This is in contrast to python, in which you can have ludicrously and arbitrarily complex chains of computation in a single line such as:
thing = A(B(size(A)(0))(0))
Walter Roberson
Walter Roberson on 6 Feb 2020
MATLAB does "really" support execution and indexing in the same line, but the syntax for it is pretty ugly. And you need a real assignment in order to capture any output after the first output from a function that returns multiple outputs.

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More Answers (1)

Azzi Abdelmalek
Azzi Abdelmalek on 6 Jun 2013
Edited: Azzi Abdelmalek on 6 Jun 2013
Look at
Example
a=[2 3 5 8]
out=arrayfun(@(x) x^2+sin(x),a)

  1 Comment

Maxim
Maxim on 6 Jun 2013
I know these functions, but don't see how they could be helpful. The problem is that I can't index the fresh array.

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