Alphabetical Sorting (case insensitive)

Question

Aiden Chrisan 2018-4-19

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/396079-alphabetical-sorting-case-insensitive

回答： Suraj Mankulangara 2018-4-23

Heyy everyone, Having small issue with my code, where i want to assort an array of words in alphabetical order (with specific case insensitive sorting). My code is;

A = ["help" ; "MATLAB" ; "anyTIME" ; "matrix" ; "alGEBra"];
[M,N]=size(A);
for i = 2:N
    char = A(i,:);
    j = i-1;

      A_j=A(j+1,:);

      A(n+1:i)=A_j(A_j>char);
      j=j-max(A_th);
      A(j+1,:) = char;

end
disp(A);

it assorts the words, but not correctly. I can successfully do this sorting with numbers no problem. And i can sort the words alphabetically with the output case sensitive(have a couple different codes but wont attach them coz i dont want to bore you lovely people). but getting the output as alphabetical AND case insensitive is proving much more problematic (NOTE: i know you could use the sort function, but i want to do it with this one for loop). Any help is much appreciated <3

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Stephen23 2018-4-19

编辑：Stephen23 2018-4-19

在 MATLAB Online 中打开

The first line

A = ["help" ; "MATLAB" ; "anyTIME" ; "matrix" ; "alGEBra"];

defines a 5x1 string array. Then you measure the size of that string array using

[M,N]=size(A);

So given that N==1, I don't see how this for loop will ever iterate even once:

for i = 2:N

Also, if A is really a string array, then char = A(i,:); is not a char vector but another string array.

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Answer 1

Suraj Mankulangara 2018-4-23

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/396079-alphabetical-sorting-case-insensitive#answer_316674

在 MATLAB Online 中打开

Hello Aiden,

Here's a simple (and likely not very efficient) bubblesort implementation of case-insensitive string array sorting:

A = ["help" ; "MATLAB" ; "anyTIME" ; "matrix" ; "alGEBra"];
[M,N]=size(A);
for i = 1:M-1
    for j = 1:M-1
        curr = A(j);
        next = A(j+1);
        if upper(curr) > upper(next)
            A(j) = next;
            A(j+1) = curr;
        end
    end
end
disp(A);

I do not quite understand why you do not want to use the in-built MATLAB "sort" function to achieve this. There is no need to reinvent the wheel. Also, the in-built functions are likely to be much more efficient and optimized. You could do case-insensitive sorting using the "sort" function by converting all characters to uppercase, like this: