MATLAB: Keeping the same order in arrays – Brain Teaser

arraymatrixmatrix manipulationvector

**EDIT: I need the output to be a matrix because a much larger part of the code needs the output of this code to be a matrix for it's input****
Hello. I have a question related to matrix manipulation.
I need to keep the order the same in the matrix. Please see below for what I am trying to do.
lets say I start out with 3 fruits:
    fruits = {'apple','orange','berry'};
and the amounts of each fruit:
    amount = [3,5,2]
then the next day the amount changes:
    amount = [2,4,3]
so now, my matrix will be:
    3  5  2
    2  4  3
but what if the next day I needed to add another fruit:
   fruits = {'apple','orange','berry','banana'};
and the amounts are:
   amount = [3,4,2,1]
how do I make my new matrix like this:
   3  5  2  NaN
   2  4  3  NaN
   3  4  2  1
then on the next day, I was not given 1 of the original fruits:
   fruits = {'apple','berry','banana'};
and the amount would be:
   amount = [5,1,4]
then I need the matrix to be like the following:
   3  5  2  NaN
   2  4  3  NaN
   3  4  2  1
   5  NaN  1  4
How would I write the code for it to be able to handle all of these situations?

Best Answer

Try using a non-scalar structure (note that looping backwards is useful and not a mistake)
fruits{4} = {'apple','berry','banana'};
amount{4} = [5,1,4];
fruits{3} = {'apple','orange','berry','banana'};
amount{3} = [3,4,2,1];
fruits{2} = {'apple','orange','berry'};
amount{2} = [2,4,3];
fruits{1} = {'apple','orange','berry'};
amount{1} = [3,5,2];
for mm = numel(fruits):-1:1 % backwards!
    for nn = 1:numel(fruits{mm})
        out(mm).(fruits{mm}{nn}) = amount{mm}(nn);
    end
end
And we can view the data:
>> {out.apple}
ans = 
    [3]    [2]    [3]    [5]
>> {out.banana}
ans = 
    []    []    [1]    [4]
Note the missing data are indicated by empty arrays.
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