If loop using cell arrays

Hi,

I have 2 matrices:

A with 24 arrays of each different length (i.e. A{1} 2362x1, A{2} 2341x1) defining salaries

B with 24 arrays of each different length (i.e. A{1} 2362x1, A{2} 2341x1) contains either a 0 or a 1

And last I have 2 boundary values C= 2600 and D= 1700.

I want to check the following:

if B(each value) == 0 && A(each value) > C
   A(this value)= C
   elseif B(each value) == 1 && A(each value) > D
   A(this value)= D
end

Can anyone help me out?

[Walter Roberson]

There is no such thing as an "if loop". There are "for loop" and there are "while loop" and there are "if statement". A loop would have to execute its body multiple times, but "if" executes the body only 1 time or 0 times.

Answer 1

[Guillaume]

You don't need any if. Just use logical operations. Your first condition is to replace elements when B is false (i.e. B==0 or simply ~B) and A greater than C, so is simply writen as A(~B & A>C). Similarly your second condition is simply A(B==1 & A>D) (which simplifies to A(B & A>D). You just have to apply that to each cell of the cell arrays:

for cellidx = 1:numel(A)
   a = A{cellidx};
   b = B{cellidx};
   a(~b & a>C) = C;
   a(b & a>D) = D;
   A{celldix} = a;
end

[Bas]

Thanks Guillaume, this is what I was searching for!

Answer 2

[Titus Edelhofer]

Hi,

I'm not 100% sure I understand what you want to do, but I guess it should be like this

for i=1:length(A)
  if all(B{i}(:)==0 & A{i}(:)>C)
    A{i}(:) = C;
  elseif all(B{i}(:)==1 & A{i}(:)>D)
    A{i}(:) = D;
  end
end

Titus

[Bas]

Hi,

thanks for your answer!

I guess this works partly, because the problem is that my matrix A consists of 1x24 cells. Each cell has a different length, i.e. A{1}= 2362x1, A{2}= 2341x1 etc. Therefore the for loop with i= 1:length(A) doesn't work well..

What I want is that none of the values in A exceed the boundary specified in either C or D, depending on the value of B, being 0 or 1 respectively.

[Titus Edelhofer]

length(A) is the length of the cell array. The code is (just as Guillaume's code) totally independent of the sizes of each A{i}, B{i} (of course as long as they match) :).

Titus

[Guillaume]

Both codes have the following preconditions:

assert(isequal(numel(A), numel(B)));
assert(all(cellfun(@(a,b) isequal(size(a), size(b)), A, B)));

[Titus Edelhofer]

I wish I could vote for a comment! Nice assert calls.