MATLAB: Compare two numeric cell arrays

cell arraysismember

I have two huge cells, a dictionary and a set of possible hands in scrabble. I want to compare the two and find what arrays match
myAletters = ['D','I','R','N','E','E','P'];
myAletters = upper(myAletters);
myAletters = int8(myAletters);
myAletters = myAletters-64;
hand_count=0;
for i=1:length(myAletters)
      hand_interim_combination=nchoosek(myAletters,i);
      for j=1:length(hand_interim_combination(:,1))
          hand_interim_permutation=perms(hand_interim_combination(j,:));
           for k=1:length(hand_interim_permutation(:,1))
               hand_count=hand_count+1;
               hand{hand_count}=hand_interim_permutation(k,:);
           end
      end
end
end
load('myDict.mat');
word_plays=ismember(hand,myDict);
Ismember won't work because it has to be strings, going one by one won't work because it takes too long. Wat do?

Best Answer

Once I got rid of that unnecessary conversion to numeric value then this task becomes a lot easier. I also preallocated the cell array hand to significantly speed the code up.
myAletters = 'DIRNEEP';
hand = cell(1,floor(exp(1)*factorial(numel(myAletters)))-1);
hand_count=0;
for i=1:length(myAletters)
      hand_interim_combination=nchoosek(myAletters,i);
      for j=1:length(hand_interim_combination(:,1))
          hand_interim_permutation=perms(hand_interim_combination(j,:));
           for k=1:length(hand_interim_permutation(:,1))
               hand_count=hand_count+1;
               hand{hand_count}=hand_interim_permutation(k,:);
           end
      end
end
%load('myDict.mat');
myDict = {'IRE','PEER','XYZ'};
word_plays = ismember(hand,myDict);
and checking the output:
>> hand(word_plays) 
ans = 
  'IRE'    'IRE'    'PEER'    'PEER'
I also tidied up the formatting (crtl+I), replaced unpredictable length with reliable size, and renamed variables to make it more readable (for me):
vec = 'DIRNEEP';
hand = cell(1,floor(exp(1)*factorial(numel(vec)))-1);
itr = 0;
for m = 1:numel(vec)
    cmb = nchoosek(vec,m);
    for n = 1:size(cmb,1)
        prm = perms(cmb(n,:));
        for k = 1:size(prm,1)
            itr = itr+1;
            hand{itr} = prm(k,:);
        end
    end
end
Perhaps the simplest solution would be to use cellstr instead of the innermost loop:
vec = 'DIRNEEP';
hand = cell(1,2^numel(vec)-1);
k = 0;
for m = 1:numel(vec)
    cmb = nchoosek(vec,m);
    for n = 1:size(cmb,1)
        k = k+1;
        hand{k} = cellstr(perms(cmb(n,:)));
    end
end
hand = vertcat(hand{:});
Note that these are all just improvements on your algorithm. With a large dictionary a more efficient algorithm might use the small number of available letters to iteratively select smaller sets of the dictionary, until matches are achieved.
Related Question