Find groups of duplicate values and preserving order?

Question

Trung Ngo 2019-6-28

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/469432-find-groups-of-duplicate-values-and-preserving-order

评论： Trung Ngo 2019-7-2

采纳的回答： Rik

在 MATLAB Online 中打开

Hi all,

I have a 100x1 double matrix

matrix=[100--100].*rand(100,1)-100;
C=unique(matrix);

I would love to create a length(C) x length(matrix) matrix which contains the positioning index from matrix to later conduct a function.

Thank you for your time,

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Rik 2019-7-2

Can you make a small example to explain what you want?

Trung Ngo 2019-7-2

在 MATLAB Online 中打开

findgroup.mat

Hi Rik, here is my code

[B, I] = sort(check_value);
lat_sorted=lat(I,:);
lon_sorted=lon(I,:);
for i=1:length(B)
    for j=1:length(B)-1
        if B(i+j)==B(i)
            if B(i)==11
                L = load('110.mat');
            elseif B(i)==12
                L = load('120.mat');
            elseif B(i)==13
                L = load('130.mat');
            elseif B(i)==14
                L = load('140.mat');
            elseif B(i)==15
                L = load('150.mat');
            elseif B(i)==16
                L = load('160.mat');
            elseif B(i)==17
                L = load('170.mat');
            elseif B(i)==18
                L = load('180.mat');
            elseif B(i)==19
                L = load('190.mat');    
            elseif B(i)==191
                L = load('191.mat');
            elseif B(i)==192
                L = load('192.mat');
            elseif B(i)==193
                L = load('193.mat');
            elseif B(i)==21
                L = load('210.mat');
            elseif B(i)==22
                L = load('220.mat');
            elseif B(i)==23
                L = load('230.mat');
            elseif B(i)==24
                L = load('240.mat');
            elseif B(i)==25
                L = load('250.mat');
            elseif B(i)==26
                L = load('260.mat');
            elseif B(i)==27
                L = load('270.mat');
            elseif B(i)==28
                L = load('280.mat');
            elseif B(i)==29
                L = load('290.mat');    
            elseif B(i)==291
                L = load('291.mat');
            elseif B(i)==292
                L = load('292.mat');
            elseif B(i)==293
                L = load('293.mat');
            elseif B(i)==31
                L = load('310.mat');
            elseif B(i)==32
                L = load('320.mat');
            elseif B(i)==33
                L = load('330.mat');
            elseif B(i)==34
                L = load('340.mat');
            elseif B(i)==35
                L = load('350.mat');
            elseif B(i)==36
                L = load('360.mat');
            elseif B(i)==37
                L = load('370.mat');
            elseif B(i)==38
                L = load('380.mat');
            elseif B(i)==39
                L = load('390.mat');    
            elseif B(i)==391
                L = load('391.mat');
            elseif B(i)==392
                L = load('392.mat');
            elseif B(i)==393
                L = load('393.mat');
            end
            for l=i:i+j
                tf(l) = interp2(L.x,L.y,L.is_land,lon_sorted(l),lat_sorted(l),'cubic');
            end
       elseif B(i+j)~=B(i)
            continue;
       end
    end
end

As you can see B(1)=B(2)=B(3)=23 and I do not want to load them 3 times, I just want to load them 1 time only and run tf(l) 3 times for l=i:i+j (in this case i=1 and j is from 1 to 2)

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Answer 1

Rik 2019-7-2

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/469432-find-groups-of-duplicate-values-and-preserving-order#answer_381660

编辑：Rik 2019-7-2

在 MATLAB Online 中打开

The code below is far from optimal, but it should help you out. It assumes there is always an L to load, and you have enough memory to store all the different mat files in a library. These assumptions are to memoization. You could improve the readability of this code by creating a masterlist of indices and file names, instead of endless elseifs. Then it is very easy to add or remove a new mat and it makes your code more readable. You can also check if the output of ismember sums to 1 to check for valid inputs.

function L=load_mat(Bi)
persistent L_libary
if isempty(L_libary),L_libary={};end
if numel(L_libary)>=Bi && ~isempty(L_libary{Bi})
    L=L_libary{Bi};
end
if Bi==11
    L = load('110.mat');
elseif Bi==12
    L = load('120.mat');
elseif Bi==13
    L = load('130.mat');
elseif Bi==14
    L = load('140.mat');
elseif Bi==15
    L = load('150.mat');
elseif Bi==16
    L = load('160.mat');
elseif Bi==17
    L = load('170.mat');
elseif Bi==18
    L = load('180.mat');
elseif Bi==19
    L = load('190.mat');
elseif Bi==191
    L = load('191.mat');
elseif Bi==192
    L = load('192.mat');
elseif Bi==193
    L = load('193.mat');
elseif Bi==21
    L = load('210.mat');
elseif Bi==22
    L = load('220.mat');
elseif Bi==23
    L = load('230.mat');
elseif Bi==24
    L = load('240.mat');
elseif Bi==25
    L = load('250.mat');
elseif Bi==26
    L = load('260.mat');
elseif Bi==27
    L = load('270.mat');
elseif Bi==28
    L = load('280.mat');
elseif Bi==29
    L = load('290.mat');
elseif Bi==291
    L = load('291.mat');
elseif Bi==292
    L = load('292.mat');
elseif Bi==293
    L = load('293.mat');
elseif Bi==31
    L = load('310.mat');
elseif Bi==32
    L = load('320.mat');
elseif Bi==33
    L = load('330.mat');
elseif Bi==34
    L = load('340.mat');
elseif Bi==35
    L = load('350.mat');
elseif Bi==36
    L = load('360.mat');
elseif Bi==37
    L = load('370.mat');
elseif Bi==38
    L = load('380.mat');
elseif Bi==39
    L = load('390.mat');
elseif Bi==391
    L = load('391.mat');
elseif Bi==392
    L = load('392.mat');
elseif Bi==393
    L = load('393.mat');
end
L_libary{Bi}=L;
end

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Trung Ngo 2019-7-2

在 MATLAB Online 中打开

Hi Rik, thank you for your details reply,

This is what I have done so far. I create a matrix that will group the dupplicate elements' index from B in 1 row.

clearvars;
load('B.mat');
k=[0,2,0];
l=diff(B);
l_add = [1; l];
in=find(l_add~=0);
out=find(l_add==0);
max=max(diff(in));
result=zeros(length(in),max+1);
for i=1:length(in)
    for j=1:max+1
        if i<length(in)
            if j==1
                result(i,j)=B(in(i));
            elseif j==2
                result(i,j)=in(i);
            else
                for l=3:max+1
                    if in(i)+l-2<in(i+1)
                        result(i,l)=in(i)+l-2;
                    elseif in(i)==in(i+1)-1
                        continue
                    else
                        continue
                    end
                end
            end
        else
            if j==1
                result(i,j)=B(in(i));
            elseif j==2
                result(i,j)=in(i);
            else
                for l=3:max+1
                    if in(i)+l-2<=out(length(out))
                        result(i,l)=in(i)+l-2;
                    end
                end
            end
        end
    end
end

From there I can reduce the search amount from 20 to 13 and apply your load_mat function, which will reduce most of the computing time

Rik 2019-7-2

Well spotted. I've edited my answer accordingly. (I've shortened your comment to include only the change for readability of this thread)

Trung Ngo 2019-7-2

Thanks Rik for your help, wish you the best

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Find groups of duplicate values and preserving order?

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Find groups of duplicate values and preserving order?

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