How to collect information of different cells in a column vector

I have a cell array x{n,j}

        <3x8 double>
  <8x9 double>
  <5x9 double>

        <2x8 double>
  <8x9 double>
  <5x9 double>

        <2x8 double>
  <8x9 double>
  <4x9 double>

        <2x8 double>
  <8x9 double>
  <3x9 double>

The information stored in various cells is to be compiled in one column vector

n is number of iterations. a=5

This code is not working

I want to collect first column of each cell into one vector

n=1:a
for j=1:columns;
[row,col]=size([x{n,j}]);
p=x{n,j}(2:row,1);
end

[Jan]

Please post the input in valid Matlab syntax. I cannot guess reliably, what "array x{n,j} double double double ..." exactly means. What is the purpose of the variable "a"? You code overwrites "p" in each iteration, but I cannot guess, what you want to get instead.

Answer 1

[Walter Roberson]

temp = cellfun(@(M) M(:,1), 'Uniform', 0);
output = vertcat(temp{:});

Answer 2

[Guillaume]

As Jan says, it's difficult to understand what you want when you don't use valid matlab syntax for your examples. An example constructing a small cell array and showing the exact desired output would be a lot more useful.

At a guess,

column1 = cellfun(@(m) m(:, 1), x, 'UniformOutput', false);
column1 = vertcat(column1{:});