フィルターのクリア

How do I gain indices of max values in 2D matrix?

8 ビュー (過去 30 日間)
Klara
Klara 2014 年 4 月 8 日
回答済み: Jos (10584) 2014 年 4 月 10 日
For a 16 x 12 matrix I should sort it in descending order to gain the max values (like 10 in total). After that, I should find what was the indices of those max values before sorting .
I tried several times with sort and find. But it doesn't give me correct result.
  2 件のコメント
Azzi Abdelmalek
Azzi Abdelmalek 2014 年 4 月 8 日
編集済み: Azzi Abdelmalek 2014 年 4 月 8 日
You have two columns, you have to precise how you want to sort them
Azzi Abdelmalek
Azzi Abdelmalek 2014 年 4 月 8 日
You have a 16x12 matrix, there are several ways to sort your matrix, by rows or by columns? you have to give more details, or just show the result for a short example, if
A=[1 2;3 4;0 1;4 5 ;100 20;2 2;0 7]
What should be the result?

サインインしてコメントする。

回答 (3 件)

Walter Roberson
Walter Roberson 2014 年 4 月 8 日
[sorted, idx] = sort(YourMatrix, 'rows', 'descend');
tenmax = idx(1:10);
  2 件のコメント
Klara
Klara 2014 年 4 月 8 日
Thanks but it gives me the indices of the max values, AFTER sorting!
Walter Roberson
Walter Roberson 2014 年 4 月 8 日
[sorted, idx] = sortrows(YourMatrix, -(1:size(YourMatrix,2)));
tenmax = idx(1:10);
this will give you the indices of the original rows that got sorted to the corresponding row position.

サインインしてコメントする。


Gautam
Gautam 2014 年 4 月 10 日
The answer above gives you the indices of before sorting. Try this example.
A = [1 4; 6 2; 4 2; 7 3]
[sortedMat,sortedIndex] = sort(A,'descend')
The sortedIndex matrix gives indices of the original rows (Note here that each column is sorted independently)

Jos (10584)
Jos (10584) 2014 年 4 月 10 日
Why sort first?
A = [1 4; 6 2; 4 2; 7 3]
[maxValues, RowIndex] = max(A,[],1)
LinearIndex = sub2ind(size(A),RowIndex, 1:size(A,2))
sortedA = sort(A,1,'descend')

カテゴリ

Help Center および File ExchangeShifting and Sorting Matrices についてさらに検索

製品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by