Matlab loop over variables (beginner)

Question

I would like to apply a function to several variables. Is there a nice way to do this?

Like:

M = ones(2,2)
N = zeros(3,3)
M = M + 1
N = N + 1

Works but I would like do something of the sort:

M = ones(2,2)
N = zeros(3,3)
L = ?UnknownStructure?(M, N)
for i = 1:length(L)
    L(i) = L(i) + 1
end

Or is there a better way entirely to apply a function to a set of variables?

I guess you could use evalin, but I wouldn't recommend it. — Ben Voigt
– Ben Voigt, Commented Jan 15, 2012 at 2:01

Oli · Accepted Answer · 2012-01-15 01:52:52Z

4

You can use cells:

M = ones(2,2)
N = zeros(3,3)
L = {M, N};
funct=@(x) x+1;
L2=cellfun(funct, L, 'UniformOutput',false);

answered Jan 15, 2012 at 1:52

Oli

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Comments

ypnos · Accepted Answer · 2012-01-15 02:01:52Z

2

There is no such thing as references in Matlab, in a sense that you can have two different variable names pointing to the same matrix.

However, you can have an array of matrices.

L = { M, N };
for i = 1:length(L)
    L{i} = L{i} + 1
end

I tested this code in Octave. However note: The source matrices M, N are unchanged by this.

answered Jan 15, 2012 at 2:01

ypnos

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carl · Accepted Answer · 2012-01-14 21:46:55Z

0

Try:

a = ones(2,2)
arrayfun(@(x) 2*x , a)

You can make the function (2*x) whatever you want.

answered Jan 14, 2012 at 21:46

carl

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I still don't see how to apply this function to several such matrices.