Help with displaying the vowels

Hi, I want to make my code to be converted to switch and case statements and have the desired output from the picture:

function [vowels] = locateVowels( charactercell )

isvowel=@(s) ismember(lower(s),'aeiou');
isvowel=@(s) ismember(lower(s),'aeiou');
idxV=cellfun(isvowel,charactercell,'unif',0);
vowels=cellfun(@(s,i) lower(s(i)),charactercell,idxV,'unif',0);
end

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Walter Roberson]

Hint:

x(ismember(x, y))

However, it is tricky to determine what the vowels are in English. See https://www.mathworks.com/matlabcentral/answers/326767-finding-vowels-in-a-string-the-user-inputs-and-printing-the-vowels-here-s-the-problem#answer_256208

[Caleb Steel]

I'm not sure how to use the hint you have given me.

[Walter Roberson]

vowels = 'aeiouàáâãäåæèéêìíîïòóôõöùúûüýāăąőűǻǽǿȺḯṍấắếớứ';
cellfun(@(s) vowels(ismember(vowels, lower(s))), test, 'uniform', 0)

The vowels list above is not complete; I got tired of going through the charts. Also, it is not impossible that some of those might have the shape of a vowel with a combining mark but might, in their respective language, not act as a vowel.

I did not attempt to sort the vowels alphabetically: they are sorted above by unicode position. For example in Polish, ą sorts immediately after a in the dictionary

[Walter Roberson]

The solution for in-order output of the vowels is:

vowels = 'aeiouàáâãäåæèéêìíîïòóôõöùúûüýāăąőűǻǽǿȺḯṍấắếớứ';
disp(cellfun(@(C) C(ismember(C,vowels)), lower(Test), 'uniform', 0))

Answer 2

[dpb]

Use the string a cell array processing features of Matlab..

test={'Opal','Otis';'Fib','Lupe'};
isvowel=@(s) ismember(lower(s),'aeiou');
idxV=cellfun(isvowel,test,'unif',0);
cellfun(@(s,i) lower(s(i)),test,idxV,'unif',0)
ans = 
  'oa'    'oi'
  'i'     'ue'

Presuming this is homework, I recommend you fully understand how it works and can reproduce it without coaching/help if asked to 'splain how you got the solution... :)

Hopefully will provide some ideas on how to more efficiently find the locations and you can then build your own solution based on those...or, if is real problem and not homework, you're more than welcome!! :)

[Caleb Steel]

This is a real problem. Also, I am not too familiar with coding, especially dealing with functions that involve cell arrays.

[dpb]

OK, does the above not then solve the problem in its entirety (other than as Walter show, the list of potential vowel characters is language dependent so have to fix that up to match your problem space)?

The difference in the two is that Walter's gives the vowels in each cell in the order in which they're found in the list of vowels; mine returns them in the order they're found in the input.

Just wrap the above in a function wrapper to pass in the input array...

function res=vowels(cellstrarray)
  isvowel=@(s) ismember(lower(s),'aeiou');
  idxV=cellfun(isvowel,cellstrarray,'unif',0);
  res=cellfun(@(s,i) lower(s(i)),cellstrarray,idxV,'unif',0);

If the list of vowels isn't fixed, then could easily add it as an (optional) second parameter.

[Caleb Steel]

The above code you gave me works fine for me, but I would like to see the code involving switch and case.

[Walter Roberson]

You cannot just disp() those things. disp() displays them in the command window. You need to store them, like

counter = 0;
switch cell{1:end,2}
  case 'a'
    counter = counter + 1;
    output(counter) = 'a';
  case 'e'
    counter = counter + 1;
    output(counter) = 'e';
end

Then once you have stored them all in the order you want, you can display the output.

Note: do not use "cell" as the name of a variable: you will intefere with the important function cell()

Note: you had the wrong syntax for switch.

Note: really, though, the line

cellfun(@(s,i) lower(s(i)),test,idxV,'unif',0)

is going to display the results anyhow, because you did not assign the result to a variable and you did not put a semi-colon on the end of the line to suppress the output.

Note: really, though, all you need to do is assign the output of that cellfun to a variable and disp() the variable. The default output when you just allow a value to be displayed is different than if you disp() the variable. dpb happens to be running an older version which naturally output in the way you would prefer.

[Caleb Steel]

So far I have the below code but "cell" has red lines under it.

function [vowels] = locateVowels( charactercell )

vowels = 0;
switch cell{1:end,2}
    case 'a'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'a';
    case 'e'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'e';
    case 'i'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'i';
    case 'o'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'o';
    case 'u'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'u';
end
end

[dpb]

"...I would like to see the code involving switch and case."

Why!?? switch construct has its place, but this really isn't it...just make more work than needs be.

[Walter Roberson]

You do not return charactercell from the function, and you do not display it, so the editor is warning you that you are wasting time in computing it.

Are you sure you want to be writing over the top of your input ?

Are you sure that you want to be using a shared variable named "cell", thereby confusing the heck out of the people who are trying to read your code? Most of whom would assume that there "cell" is trying to refer to the function cell(), or else that "cell" is referring there to an uninitialized variable?

If the point is only to count the vowels then why bother storing them?

[Caleb Steel]

When I do not include "cell", "end" is underlined.

function [vowels] = locateVowels( charactercell )

vowels = 0;
switch {1:end,2}
    case 'a'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'a';
    case 'e'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'e';
    case 'i'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'i';
    case 'o'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'o';
    case 'u'
        charactercell = charactercell + 1;
        vowels(charactercell) = 'u';
end
end

[Walter Roberson]

Sigh.

function [vowels] = locateVowels( charactercell )

    vowels = '';
    vowelcount = 0;
    for row = 1 : length(charactercell)
      thisentry = charactercell{row, 2};
      switch thisentry
          case 'a'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'a';
          case 'ä'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'ä';
          case 'e'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'e';
          case 'ë'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'ë';
          case 'é'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'é';
          case 'i'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'i';
          case 'ï'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'ï';
          case 'o'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'o';
          case 'ö'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'ö';
          case 'u'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'u';
          case 'ü'
              vowelcount = vowelcount + 1;
              vowels(vowelcount) = 'ü';
      end
    end

end

Note: all of the above are used in English. https://en.wikipedia.org/wiki/English_terms_with_diacritical_marks

[Caleb Steel]

When I try to run this code, the output results in 0x0 char array. I want the output to be a 2x2 cell array

[Walter Roberson]

function [vowels] = locateVowels( charactercell )

    vowels = cell(size(charactercell));

    for cell_idx = 1 : numel(charactercell)
      thesevowels = '';
      vowelcount = 0;
      thisentry = charactercell{cell_idx};
      for str_idx = 1 : length(thisentry)
        switch lower(thisentry(str_idx))
          case 'a'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'a';
          case 'ä'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'ä';
          case 'e'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'e';
          case 'ë'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'ë';
          case 'é'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'é';
          case 'i'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'i';
          case 'ï'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'ï';
          case 'o'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'o';
          case 'ö'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'ö';
          case 'u'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'u';
          case 'ü'
              vowelcount = vowelcount + 1;
              thesevowels(vowelcount) = 'ü';
        end
      end
      vowels{cell_idx} = thesevowels;
    end

end

This is an approach I would never take, and is suitable only for an exercise in proving that one knows how to use the switch construct and cell arrays.

[Caleb Steel]

Thank you so much!