Question

I have data in Matlab that is in cell array format with columns representing different items. The cell arrays have different columns, as in the following example:

a = {'A', 'B', 'C' ; 1, 1, 1; 2, 2, 2 }

a =

'A'    'B'    'C'
[1]    [1]    [1]
[2]    [2]    [2]

b = {'C', 'D'; 3, 3; 4, 4}

b =

'C'    'D'
[3]    [3]
[4]    [4]

I would like to be able to join the different cell arrays in the following manner:

c =

'A'    'B'    'C'    'D'
[1]    [1]    [1]    [NaN]
[2]    [2]    [2]    [NaN]
[NaN]  [NaN]  [3]    [3]
[NaN]  [NaN]  [4]    [4]

In the real example I have hundreds of columns and several rows, so creating a new cell array manually is not an option for me.

Answer 1

If you were willing to store your data in dataset arrays (or convert them to dataset arrays for this purpose), you could do the following:

>> d1
d1 = 
    A    B    C
    1    1    1
    2    2    2
>> d2
d2 = 
    C    D
    3    3
    4    4
>> join(d1,d2,'Keys','C','type','outer','mergekeys',true)
ans = 
    A      B      C    D  
      1      1    1    NaN
      2      2    2    NaN
    NaN    NaN    3      3
    NaN    NaN    4      4