Hello. I have to write a function called occurrence that tests whether a character exists in a string. If it is present, display true and the position (index) of the character. If it is not present, return inf. it gives me an error in line 2. help?!?

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Naagy Omar 2019-12-19

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评论： Naagy Omar 2019-12-19

function find_letter(L, string)
    n= 1:length(L);
    not_found = true; 
       for k = 1:n
          if isequal(L(k).letter, string)
             fprintf('letter %s is present! It is the %2.0d item\n', L(k).title, k);
             not_found = false; 
             break; % or return 
          end
       end 
     if not_found; fprintf('letter not present\n')
     end
    

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Rik 2019-12-19

How do you call this function? Also, you're generating a vector for your loop twice, and you haven't set the output to inf yet.

Naagy Omar 2019-12-19

编辑：Naagy Omar 2019-12-19

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thank you my friend!

Ive edited the code, but it still gives me an error. i tried just clicking "run" but it doesn't work. I also tried calling the function using "find_character('itscoldtoday, o')" but it returns error in line 3.

function find_character(L, string)
    not_found = true; 
       for k = 1:length(L);
          if isequal(L(k).character, string)
             fprintf('character %s is present! It is the %2.0d item\n', L(k).title, k);
             not_found = false; 
             break; % or return 
          end
       end 
     if not_found; fprintf('Inf\n')
     end
end

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Answer 1

Chuguang Pan 2019-12-19

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https://ww2.mathworks.cn/matlabcentral/answers/497357-hello-i-have-to-write-a-function-called-occurrence-that-tests-whether-a-character-exists-in-a-strin#answer_407056

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function find_letter(L, string)
    n= length(L);
    not_found = true; 
       for k = 1:n
          if isequal(L(k), string)
             fprintf('letter %s is present! It is the %2.0d item\n', L(k), k);
             not_found = false; 
             break; % or return 
          end
       end 
     if not_found; fprintf('letter not present\n')
     end
    find_letter('Hello World!','o');

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Naagy Omar 2019-12-19

Hello!

It still gives me error in line 2. I can't figure out why?

Naagy Omar 2019-12-19

在 MATLAB Online 中打开

Thank you for your help! Hey I tried this and it works!

find_letter('itscoldtoday!','y');
function find_letter(L, string)
    not_found = true; 
       for k = 1:strlength(L);
          if isequal(L(k), string)
             fprintf('letter %s is present! It is the %2.0d item\n', L(k), k);
             not_found = false; 
             break; % or return 
          end
       end 
     if not_found; fprintf('letter not present\n')
     end
end