Moving NaN elements from the last columns to the first column, iteratively

Question

gd94 2019-6-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/466365-moving-nan-elements-from-the-last-columns-to-the-first-column-iteratively

评论： TADA 2019-6-11

Hello community,

I'm struggling to figure out a way to automatize a problem I'm confronting on Matlab. Here is a fictitious matrix that replicates my issue (mine is much bigger, but always has between 0 and 2 NaN observations at the end of the matrix):

A = [1 2 3 4 5 6 7 8 NaN NaN;

1 2 3 4 5 6 7 8 9 NaN;

1 2 3 4 5 6 7 8 9 10]

For those rows that have NaNs, I want to move the NaN observations to the front of the matrix, so as to have this;

A = [NaN NaN 1 2 3 4 5 6 7 8;

NaN 1 2 3 4 5 6 7 8 9;

1 2 3 4 5 6 7 8 9 10]

This is a code which works for me with a row vector (i.e A = [1 2 3 4 5 6 7 8 NaN NaN]):

while isnan(A(end))

A = A(1:end-1);

A = [NaN,A];

end

I can't seem to figure out how to broaden the loop to the general case presented above (the 3x10 matrix).

Thank you!

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

TADA 2019-6-10

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/466365-moving-nan-elements-from-the-last-columns-to-the-first-column-iteratively#answer_378603

编辑：TADA 2019-6-11

在 MATLAB Online 中打开

The simplest way would be to loop through the rows:

i = isnan(A);
for j = 1:size(A,1)
  A(j,:)  = [A(j,i(j,:)) A(j,~i(j,:))];
end

Another approach:

a1 = A';
[~, ord] = sort(~isnan(a1));
ord2 = ord + repmat(0:size(a1,1):numel(a1)-1, size(a1,1),1);
a2 = a1(ord2)'

3 个评论
显示 1更早的评论隐藏 1更早的评论

gd94 2019-6-11

Works.... great! Thank you so much TADA

TADA 2019-6-11

cheers no problem

请先登录，再进行评论。

Answer 2

Bob Thompson 2019-6-10

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/466365-moving-nan-elements-from-the-last-columns-to-the-first-column-iteratively#answer_378577

Do you want your numeric values in ascending order? If so you should be able to do the following:

A = sort(A,2,'MissingPlacement','first');

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

gd94 2019-6-11

No, not necessarily. The 1 2 3 ..... 9 were just examples of numbers, but they need not be in ascending order. The order should just be maintained when moving the NaNs to the front.

请先登录，再进行评论。