Logical vector based on matrix rows

Question

ARS 2013-2-22

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/64542-logical-vector-based-on-matrix-rows

Let's say I have the matrix

A =
    -2     1     2
     1     2     3
     3     1     2
     4     3     4
     1     1     2

and I want a logical vector in which the nth element is 1 if A(n,2:end) == [1 2] (for instance) and 0 otherwise. So in this case the result would be [1 0 1 0 1]. Of course this is just a random example, but what would be an easy, general solution to achieve this, for arbitrary matrix A (in this case as above) and row vector v (in this case [1 2])?

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Answer 1

Azzi Abdelmalek 2013-2-22

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https://ww2.mathworks.cn/matlabcentral/answers/64542-logical-vector-based-on-matrix-rows#answer_76120

编辑：Azzi Abdelmalek 2013-2-22

在 MATLAB Online 中打开

out=ismember(A(:,2:end),[1 2],'rows')'

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Answer 2

Mark Whirdy 2013-2-22

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/64542-logical-vector-based-on-matrix-rows#answer_76121

编辑：Mark Whirdy 2013-2-22

在 MATLAB Online 中打开

Please Press "accept" if this answers your question

%% YOUR EXAMPLE A = [... -2 1 2; 1 2 3; 3 1 2; 4 3 4; 1 1 2]; a = [1,2];

    fn = @(A,a)(sum(A(:,end-size(a,2)+1:end)==repmat(a,size(A,1),1),2)==size(a,2)); % anonymous function
>> fn(A,a)
ans =
     1
     0
     1
     0
     1

%% ANOTHER EXAMPLE

   A = [...
       -2     1     2   3 ;
       1     2     3    3;
       3     1     2   4;
       4     3     4    4;
       1     1     2   3];
  a = [1,2,3];
  >> fn(A,a)
  ans =
       1
       0
       0
       0
       1