unique set from file

I have a .mat file with 14994x31 cells with random alphabets in the cells. I need to find the unique set. I know it is going to be the set of all alphabets only. But I want to find exactly which alphabets are present (if not all). Is the anyway to find out the unique set for the entire file and not just row by row?

[Adam Danz]

Could you give us an example of the cell array?

[Sanjana Sankar]

'!' 'a:' 'l' 't' '@' [] []

'?' 'a:' 'l' 't' '@' 's' 't'

'/' 'a' 'b' 'a' 'n' 'd' 'A~'

3 different rows

Answer 1

[Adam Danz]

c = {'!'	'a:'	'l'	't'	'@'	[]	[]	
'?'	'a:'	'l'	't'	'@'	's'	't'	
'/'	'a'	'b'	'a'	'n'	'd'	'A~'}; 

cUnq = unique(c(cellfun(@ischar,c))); 

Result

cUnq =
  13×1 cell array
    {'!' }
    {'/' }
    {'?' }
    {'@' }
    {'A~'}
    {'a' }
    {'a:'}
    {'b' }
    {'d' }
    {'l' }
    {'n' }
    {'s' }
    {'t' }

If you want to keep the unique elements in their original order,

cUnq = unique(c(cellfun(@ischar,c)),'stable');

Answer 2

[Joel Handy]

 c = {'!'	'a:'	'l'	't'	'@'	[]	[]	
'?'	'a:'	'l'	't'	'@'	's'	't'	
'/'	'a'	'b'	'a'	'n'	'd'	'A~'}; 

for rowIdx = 1:size(c,1)
    cString(rowIdx) = string([c{rowIdx,:}])
end

uniqueSets = unique(cString)

[Sanjana Sankar]

Thank you. This also works!!