How to sort rows?

Question

Noor Fatima 2022-10-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1823533-how-to-sort-rows

评论： David Hill 2022-10-13

采纳的回答： David Hill

>> A = [1 2; 4 3; 3 5; 2 1; 1 3; 4 5]

A =

1 2

4 3

3 5

2 1

1 3

4 5

>> B = sortrows(A)

B =

1 2

1 3

2 1

3 5

4 3

4 5

How to sort B, if entries of A are in java.math.BigInteger?

1 个评论
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Torsten 2022-10-12

uint64 as a MATLAB data type is not sufficient for your purpose ?

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Answer 1

David Hill 2022-10-12

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1823533-how-to-sort-rows#answer_1072708

在 MATLAB Online 中打开

import java.math.*
%load sample BigInteger Array (100x2)
for k=1:100
  J(k,:)=[BigInteger(repmat(num2str(randi(1e14,1)),1,3)),BigInteger(repmat(num2str(randi(1e14,1)),1,3))];
end
%have to do sort manually, any sort algorithm will work but need to use
%compareTo() for BigIntegers
c=0;
while c~=size(J,1)-1
    c=0;
    for k=1:size(J,1)-1
        if J(k,1).compareTo(J(k+1,1))<1
            c=c+1;
        else
            temp=J(k+1);
            J(k+1)=J(k);
            J(k)=temp;
        end
    end
end

3 个评论
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Noor Fatima 2022-10-12

@David Hill May I request for the following

The above code sort perfectly fine w.r.t first coordinate.

But if first coordinate is the same, it is not sorting w.r.t second coordinate. Like it can be done with sortrows in the above-mentioned B.

David Hill 2022-10-13

在 MATLAB Online 中打开

import java.math.*
%load sample BigInteger Array (100x2)
for k=1:100
  J(k,:)=[BigInteger(repmat(num2str(randi(1e14,1)),1,3)),BigInteger(repmat(num2str(randi(1e14,1)),1,3))];
end
%have to do sort manually, any sort algorithm will work but need to use
%compareTo() for BigIntegers
c=0;
while c~=size(J,1)-1
    c=0;
    for k=1:size(J,1)-1
        if J(k,1).compareTo(J(k+1,1))==0&&J(k,2).compareTo(J(k+1,2))==1
            temp=J(k+1);
            J(k+1)=J(k);
            J(k)=temp;
        elseif J(k,1).compareTo(J(k+1,1))<1
            c=c+1;
        else
            temp=J(k+1);
            J(k+1)=J(k);
            J(k)=temp;
        end
    end
end