Finding min values of third column for rows with similar values

Question

ahmad Mohammadi 2020-8-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/577864-finding-min-values-of-third-column-for-rows-with-similar-values

编辑： ahmad Mohammadi 2020-8-11

采纳的回答： Stephen23

Hi,

I have a Table

2.0000 0 3.1971

1.0000 0 3.1971

3.0000 0 6.4662

1.0000 0 6.4662

3.0000 0 9.6356

2.0000 0 9.6356

2.0000 1 7

1.0000 1 5

3.0000 1 6

1.0000 1 10

3.0000 1 44

2.0000 1 12

Now, what I want is that find minimum value of third column for the first column with equal value in each loop of second column.

Maybe it is better to see the result what I mean.

2.0000 0 3.1971

1.0000 0 3.1971

3.0000 0 6.4662

2.0000 1 7

1.0000 1 5

3.0000 1 6

Really appreciate

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Stephen23 2020-8-11

编辑：Stephen23 2020-8-11

在 MATLAB Online 中打开

The example is not clear for me. You wrote that you want the "...minimum value of third column...", can you please explain why your example output contains this row:

...
    2.0000         1    7
...

when the input matrix contains both of these rows

...
    2.00000    1.00000    7.00000
...
    2.00000    1.00000    2.00000

As far as I can tell, 2 is less than 7, so why does the expected output not contain the "minimum value" ?

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Answer 1

Stephen23 2020-8-11

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/577864-finding-min-values-of-third-column-for-rows-with-similar-values#answer_477919

编辑：Stephen23 2020-8-11

在 MATLAB Online 中打开

>> M = [2.0000,0,3.1971;1.0000,0,3.1971;3.0000,0,6.4662;1.0000,0,6.4662;3.0000,0,9.6356;2.0000,0,9.6356;2.0000,1,7;1.0000,1,5;3.0000,1,6;1.0000,1,10;3.0000,1,44;2.0000,1,2]
M =
0000         0    3.1971
0000         0    3.1971
0000         0    6.4662
0000         0    6.4662
0000         0    9.6356
0000         0    9.6356
0000    1.0000    7.0000
0000    1.0000    5.0000
0000    1.0000    6.0000
0000    1.0000   10.0000
0000    1.0000   44.0000
0000    1.0000    2.0000
>> [U,X,Y] = unique(M(:,1:2),'stable','rows');
>> V = accumarray(Y,M(:,3),size(X),@min);
>> A = [U,V]
A =
0000         0    3.1971
0000         0    3.1971
0000         0    6.4662
0000    1.0000    2.0000
0000    1.0000    5.0000
0000    1.0000    6.0000