Removing Rpeated Values from a Matrix

Question

Sarvesh Kumar 2018-6-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/404671-removing-rpeated-values-from-a-matrix

评论： Sarvesh Kumar 2018-6-8

采纳的回答： Stephen23

Hi

I have a matrix below:

NaN NaN

518460 3.3220

518460 -12.9840

518520 3.7890

518520 -10.2800

518580 7.6730

518580 16.8510

518640 5.9590

.

the values in the 1st column are repeated (2-4 times). i want to write a code which checks the values in the 1st column, if it is repeated, then it will read the respective 2nd column values and only keep the row with the largest 2nd column value while deleting the other rows. so the matrix above when ran through the code should be:

518460 3.3220

518520 3.7890

518580 7.6730

518580 16.8510 .

.

the data exceeds over 1000 entries but i have only given a small piece of it above.

how can i write the code so i get my second matrix from the first.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Stephen23 2018-6-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/404671-removing-rpeated-values-from-a-matrix#answer_323787

编辑：Stephen23 2018-6-8

在 MATLAB Online 中打开

>> M = [518460,3.3220;518460,-12.9840;518520,3.7890;518520,-10.2800;518580,7.6730;518580,16.8510;518640,5.9590]
M =
   518460        3.32200
   518460      -12.98400
   518520        3.78900
   518520      -10.28000
   518580        7.67300
   518580       16.85100
   518640        5.95900
>> [uni,~,idx] = unique(M(:,1));
>> val = accumarray(idx,M(:,2),[],@max);
>>  [uni,val]
ans =
   518460        3.32200
   518520        3.78900
   518580       16.85100
   518640        5.95900