用NaN排序矩阵，提取索引向量并将NaN移到末尾 [英] Sort matrix with NaNs, extract index vectors and move NaNs to the end

问题描述

mockup = [3,5,nan,2,4,nan,10,nan];

如何在不考虑NaN的情况下按降序对向量进行排序?所得向量的长度必须与mockup相同，即我需要将所有NaN放在末尾.结果应该像这样: mockupSorted = [10,5,4,3,2,NaN,NaN,NaN]

How can I sort this vector in a descending order while ignoring the NaNs? The resulting vector must have the same length as mockup, i.e. I need to put all NaNs at the end. The result should like like this: mockupSorted = [10,5,4,3,2,NaN,NaN,NaN]

实际上，我对各个索引感兴趣，即sort函数的第二个输出向量.所以，我在寻找 mockupSortedIdx = [7,2,5,1,4,NaN,NaN,NaN]

Actually, I am interested in the respective indices, i.e. the second output vector of the sort function. So, I am looking for mockupSortedIdx = [7,2,5,1,4,NaN,NaN,NaN]

推荐答案

您可以使用sort的两个输出，然后使用isnan修改两个输出的顺序.

You can use the two outputs of sort and then use isnan to modify the ordering of the two outputs.

[vals, inds] = sort(mockup, 'descend');

bool = isnan(vals);

mocksorted = [vals(~bool), vals(bool)];
%    10     5     4     3     2   NaN   NaN   NaN

mocksortedind = [inds(~bool), vals(bool)];
%     7     2     5     1     4   NaN   NaN   NaN

另一种选择是使用ascend排序，并对mockup的负数进行排序，因为ascend排序会将NaN值放在末尾.

The other option is to use ascend sort and just sort the negative of mockup since the ascend sort will place the NaN values at the end.

[vals, inds] = sort(-mockup);

mocksorted = -vals;
mocksortedind = inds;

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