How to fill end of rows of a matrix with NaN values?

16 次查看（过去 30 天）
Mr M.
Mr M. 2021-6-1
回答： Walter Roberson 2021-6-2
I have a matrix M, and vector of indices K. I would like to make an element M(k,j) = NaN if j >= K(k). It is possible to do this with a vectorized short methode?
  2 个评论
Bob Thompson
Bob Thompson 2021-6-1
编辑：Bob Thompson 2021-6-1
Why not just preallocate the matrix with nan values? Do you have any idea of the max size your matrix could be?
M = nan(max(k),max(j));
Mr M.
Mr M. 2021-6-2
I think, you misunderstood my problem. Lets see an example.
let M be: [1,2,3; 1,2,3; 1,2,3; 1,2,3]; An let K be: [2; 3; 1; NaN or 4 or anithing else]. This means I need the following output:
[1;NaN,NaN; 1,2,NaN; NaN,NaN,NaN; 1,2,3]

请先登录，再进行评论。

请先登录，再回答此问题。

回答（2 个）

Sulaymon Eshkabilov
Hi,
here is a simple solution, e.g.:
M = magic(5);
M(:,end)=nan
Walter Roberson
Walter Roberson 2021-6-2
Ran in:
M = [1,2,3; 1,2,3; 1,2,3; 1,2,3]
M = 4×3
1 2 3 1 2 3 1 2 3 1 2 3
K = [2; 3; 1; NaN]
K = 4×1
2 3 1 NaN
M((1:size(M,2)) >= K(:)) = nan
M = 4×3
1 NaN NaN 1 2 NaN NaN NaN NaN 1 2 3

类别

在 Help Center 和 File Exchange 中查找有关 Matrix Indexing 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by