How to use the index ? how to drop elements from a matrix ?

Question

Islam 2013-11-30

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/108103-how-to-use-the-index-how-to-drop-elements-from-a-matrix

回答： Andrei Bobrov 2013-11-30

采纳的回答： Wayne King

在 MATLAB Online 中打开

I have a matrix b(j,w) = b(3,4)

b= [

0913       NaN       NaN       NaN
0913       NaN       NaN       NaN
0913       NaN       NaN       NaN ]

and g(j,w)=g(3,4)

  60    60    60
  70    70    70
  75    75    75

I want to drop the elements in g that have a correspondent NAN value in b.

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Answer 1

Wayne King 2013-11-30

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https://ww2.mathworks.cn/matlabcentral/answers/108103-how-to-use-the-index-how-to-drop-elements-from-a-matrix#answer_116803

编辑：Wayne King 2013-11-30

在 MATLAB Online 中打开

One of many ways:

b= [
    0.0913       NaN       NaN       NaN
    0.0913       NaN       NaN       NaN
    0.0913       NaN       NaN       NaN ];
  g = [60    60    60    60
    70    70    70    70
    75    75    75    75];
  idx = ~isnan(b);
  g = g(idx>0);

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Answer 2

Azzi Abdelmalek 2013-11-30

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https://ww2.mathworks.cn/matlabcentral/answers/108103-how-to-use-the-index-how-to-drop-elements-from-a-matrix#answer_116804

在 MATLAB Online 中打开

b= [ 0.0913       NaN       NaN       NaN
  0.0913       NaN       NaN       NaN
  0.0913       NaN       NaN       NaN ]
c=[ 60    60    60    60
  70    70    70    70
  75    75    75    75]
idx=any(~isnan(b),1)
c=c(:,idx)

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Answer 3

Andrei Bobrov 2013-11-30

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/108103-how-to-use-the-index-how-to-drop-elements-from-a-matrix#answer_116805

在 MATLAB Online 中打开

b =   [0.0913          NaN          NaN          NaN
       0.0913          NaN          NaN          NaN
       0.0913          NaN          NaN          NaN];
g = [60    60    60    60
    70    70    70    70
    75    75    75    75];
>> g(~isnan(b))
ans =
    60
    70
    75