combine different size vectors into one matrix

I need to combine sets of data I have together into one matrix, but they have different dimensions.

this is a simplified example:

e=[2 3 4 5];
>> ee=[4 7 7];
>> eee=[8 8 7 4 2 5];
>> p=[e; ee; eee];

I want to fill nan to make them even, but I don't know how.

I want each vector to be in a raw, so I get something like that

p=[2 3 4 5 NaN NaN;

4 7 7 NaN NaN NaN;

8 8 7 4 2 5];

then I want to get the mean for each column data

any suggestions please.

Answer 1

[Chunru]

% use a cell array instead of separate variables
e{1}=[2 3 4 5];
e{2}=[4 7 7];
e{3}=[8 8 7 4 2 5];

% find the longest vector
l = max(cellfun(@(x) length(x), e))

l = 6

y = nan(length(e), l);
for i=1:length(e)
    y(i, 1:length(e{i})) = e{i};
end
y

y = 3×6

2 3 4 5 NaN NaN 4 7 7 NaN NaN NaN 8 8 7 4 2 5

ym = mean(y, 1, 'omitnan')   % mean along 1st dimension or column

ym = 1×6

4.6667 6.0000 6.0000 4.5000 2.0000 5.0000

[Suzuki]

thank you very much, it worked.

[Suzuki]

@Matt J @Chunru

if I may ask one more question,

so, when reachin the point of calculating the mean of each column, I can use

mean(ww(:,1),'omitnan') and so on, but I have a 46 column, how to for loop it??

[Chunru]

See above.

[Suzuki]

right, thanks alot.

Answer 2

[Matt J]

I will assume you have the vectors in a cell array

C={[2 3 4 5];
   [4 7 7];
   [8 8 7 4 2 5]}

C = 3×1 cell array
    {[    2 3 4 5]}
    {[      4 7 7]}
    {[8 8 7 4 2 5]}

Then, you can simply do,

z=max(cellfun('length',C));

p=cell2mat( cellfun(@(x)[x,nan(1,z-numel(x) )]  ,C,'uni',0))

p = 3×6

2 3 4 5 NaN NaN 4 7 7 NaN NaN NaN 8 8 7 4 2 5

[Suzuki]

thank you very much.

I works, but it fill them all in one row.