Removal of duplicate entries and counting them

Hi, Sorry if I have asked a dumb question, but I am new to matlab. So please bear with me. I want to create a matlab script that calculates the number of duplicate entries from an array and also removes them. Can you please let me know how can it be done ? I will further explain my question with the help of an example.

a[] = the the she he she she

so the output should be :

the - 2 times she - 3 times he - 1 time/s

I was thinking of using the for loop and comparing each and every elements with one another. But I am having problems in eliminating duplicate data.

Thank you, Sean

Answer 1

[Matt Fig]

You could use a loop, or do something like this:

a = {'the' 'the' 'she' 'he' 'she' 'she'}
[V,N,X] = unique(a);
N = histc(X,1:length(N));

Now look at V and N. N tells you that there is 1 he, 3 she and 2 the.

Answer 2

[Matt Tearle]

If you happen to have access to Statistics Toolbox, and you are actually messing with strings (like in your example), you might want to consider using nominal arrays:

a = nominal({'the' 'the' 'she' 'he' 'she' 'she'});
tokens = getlevels(a)
n = hist(a)

Nominal arrays take less memory and have some other nice features.

Answer 3

[Andrew Newell]

a = {'the', 'the', 'she', 'he', 'she', 'she'};
au = unique(a); % This finds one of each string

% strcmp gives a logical vector with 1 for each match and 
% zero otherwise
str = [];
for i=1:numel(au)
    numDuplicates = sum(strcmp(au(i),a));
    str = [str,au{i},' - ',num2str(numDuplicates),' times '];
end

disp(str)