Best way to reduce to a simple loop?

Question

Oscar Zampi 2021-2-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/751294-best-way-to-reduce-to-a-simple-loop

回答： Jan 2021-2-21

Hi, I have the following section of code that I would like to simplify down as much as possible so that it can do the same thing, but am unsure how to do so.

Any help would be greatly apopreciated!

if A(1,3)<A(2,3) && A(1,3)<A(3,3) && A(1,3)<A(4,3) && A(1,3)<A(5,3)
      E1i = A(1,1);
      E1j = A(1,2);
      E1y = 913000 - E1i;
      E1x = E1j + 207000;
      plot(E1x, E1y,'rx')
      A(1,:) = [];
else if A(2,3)<A(1,3) && A(2,3)<A(3,3) && A(2,3)<A(4,3) && A(2,3)<A(5,3)
          E1i = A(2,1);
          E1j = A(2,2);
          E1y = 913000 - E1i;
          E1x = E1j + 207000;
          plot(E1x, E1y,'rx')
          A(2,:) = [];
    else if A(3,3)<A(1,3) && A(3,3)<A(2,3) && A(3,3)<A(4,3) && A(3,3)<A(5,3)
              E1i = A(3,1);
              E1j = A(3,2);
              E1y = 913000 - E1i;
              E1x = E1j + 207000;
              plot(E1x, E1y,'rx')
              A(3,:) = [];
        else if A(4,3)<A(1,3) && A(4,3)<A(2,3) && A(4,3)<A(3,3) && A(4,3)<A(5,3)
                  E1i = A(4,1);
                  E1j = A(4,2);
                  E1y = 913000 - E1i;
                  E1x = E1j + 207000;
                  plot(E1x, E1y,'rx')
                  A(4,:) = [];
            else A(5,3)<A(1,3) && A(5,3)<A(2,3) && A(5,3)<A(3,3) && A(5,3)<A(4,3)
                  E1i = A(5,1);
                  E1j = A(5,2);
                  E1y = 913000 - E1i;
                  E1x = E1j + 207000;
                  plot(E1x, E1y,'rx')
                  A(5,:) = [];
            end
            
        end
    end
end
if A(1,3)<A(2,3) && A(1,3)<A(3,3) && A(1,3)<A(4,3) 
      E1i = A(1,1);
      E1j = A(1,2);
      E1y = 913000 - E1i;
      E1x = E1j + 207000;
      plot(E1x, E1y,'rx')
      A(1,:) = [];
else if A(2,3)<A(1,3) && A(2,3)<A(3,3) && A(2,3)<A(4,3) 
          E1i = A(2,1);
          E1j = A(2,2);
          E1y = 913000 - E1i;
          E1x = E1j + 207000;
          plot(E1x, E1y,'rx')
          A(2,:) = [];
    else if A(3,3)<A(1,3) && A(3,3)<A(2,3) && A(3,3)<A(4,3) 
              E1i = A(3,1);
              E1j = A(3,2);
              E1y = 913000 - E1i;
              E1x = E1j + 207000;
              plot(E1x, E1y,'rx')
              A(3,:) = [];
        else if A(4,3)<A(1,3) && A(4,3)<A(2,3) && A(4,3)<A(3,3) 
                 E1i = A(4,1);
                 E1j = A(4,2);
                 E1y = 913000 - E1i;
                 E1x = E1j + 207000;
                 plot(E1x, E1y,'rx')
                 A(4,:) = [];
            end
        end
    end
end
if A(1,3)<A(2,3) && A(1,3)<A(3,3) 
      E1i = A(1,1);
      E1j = A(1,2);
      E1y = 913000 - E1i;
      E1x = E1j + 207000;
      plot(E1x, E1y,'rx')
      A(1,:) = [];
else if A(2,3)<A(1,3) && A(2,3)<A(3,3) 
          E1i = A(2,1);
          E1j = A(2,2);
          E1y = 913000 - E1i;
          E1x = E1j + 207000;
          plot(E1x, E1y,'rx')
          A(2,:) = [];
    else if A(3,3)<A(1,3) && A(3,3)<A(2,3) 
              E1i = A(3,1);
              E1j = A(3,2);
              E1y = 913000 - E1i;
              E1x = E1j + 207000;
              plot(E1x, E1y,'rx')
              A(3,:) = [];
        end
    end
end

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Adam Danz 2021-2-20

😨

Before the loops are optimized, there are some serious problems to address with the existing code.

The indentation make is very difficult to understand how these conditions are nested. From the Matlab editor, select all of the text (ctrl+a) and then smart-indent (ctrl+i).
Look at all of the orange tick marks along the right side of the editor. They indicate warnings. Not all warnings are serious but the ones listed here are serious.
"else if" is must different from "elseif". Please review the documentation: doc elseif
Edit your question to clean up the code so that it represents what you want it to do and fix the problems listed above.

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Answer 1

Jan 2021-2-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/751294-best-way-to-reduce-to-a-simple-loop#answer_628869

在 MATLAB Online 中打开

The first block can be simplified to:

i2    = 2;    % This is 2 in the first iteration, and 1 afterwards
index = NaN;
for i1 = 1:5
   if A(i1,3)<A(i2,3) && A(i1,3)<A(3,3) && A(i1,3)<A(4,3) && A(i1,3)<A(5,3)
       index = i1:
       break;
   end
   i2 = 1;
end
E1i = A(index,1);
E1j = A(index,2);
E1y = 913000 - E1i;
E1x = E1j + 207000;
plot(E1x, E1y,'rx')
A(index, :) = [];