converting only certain cells to a matrix

consider the following example

    a = { rand(1877958,7); rand(1251972,7); rand(4564357,7) };

i want only the first two cells to be converted to a matrix. i know that the rows are not the same but the remaining rows can be filled with zeros. how can i do that in such a way so that the output has 14 columns meaning the matrices are put adjacent to each other. thanks

Answer 1

[Azzi Abdelmalek]

a = { rand(1877958,7); rand(1251972,7); rand(4564357,7) };
n=max(cellfun(@(x) size(x,1) , a(1:2)) )
b=cell2mat(cellfun(@(x) [x;zeros(n-size(x,1),7)],a(1:2)','un',0));

[AA]

Is there a way to do this conversion without the zeros?

[Azzi Abdelmalek]

How? you must get the same number of rows if you want to concatenate them horizontally

[AA]

You are right. Your formula concentrates them vertically. How can i concentrate the tables horizontally so that i get 14 columns. Thanks

[Azzi Abdelmalek]

No, they are horizontally concatenated, look at the size, it's 1877958x14

[AA]

I apologize. You r right. How would I vertically arrange the tables without zeros and 7 columns. Thanks

[Azzi Abdelmalek]

This is easier

b=cell2mat(a(1:2));