how to find common values in two matrix for particular column?

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Shubham Mohan Tatpalliwar 2018-10-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/425836-how-to-find-common-values-in-two-matrix-for-particular-column

编辑： Bruno Luong 2018-10-25

if true
  % code
A=[0 1 1 0; 1 0 0 1; 1  1 0 0; 0 0 1 1]
B=[0 1 0 1; 1 0 1 0; 0 0 1 1; 1 1 0 0]
end

for 1st column of A and ALL columns of b

if we check

the expected answer is

1 0 2 1

these are the total number of instances they are matching

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Bruno Luong 2018-10-24

Please put care on

code formatting
explanation
formulation of synthetic question (Why give the whole A and ask just result that depends only on first column)

Shubham Mohan Tatpalliwar 2018-10-24

in the first column of A, there are two ones at 2nd row and 3 rd row

so considering this it will check all columns of B

in the first column of B, there is 1 in 2nd row that match and it did not match with the 3rd row

so for 1st column of B answer is 1

for 2nd column of B and 1st column of A nothing match so the answer is zero

Further for the 3rd column of B and 1st column A the second and 3rd row of both are 1 so the answer is 2

and so on...

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采纳的回答

Bruno Luong 2018-10-24

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/425836-how-to-find-common-values-in-two-matrix-for-particular-column#answer_343159

在 MATLAB Online 中打开

>> sum(A(:,1)+B==2)

ans =

1 0 2 1

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Shubham Mohan Tatpalliwar 2018-10-25

can u explain a bit about this code?

Bruno Luong 2018-10-25

编辑：Bruno Luong 2018-10-25

The reshape() just moves the 2nd dimension (column) of A to the 3rd dimension

So each origin column A(:,j) now can be addressed as A(:,:j).

The explanation for SUM(... & B) you already know, but now use in the context of auto-expansion. Excepted that the result now is of the size (1 x size(B,2) x size(A,2)): each number of common 1-values of B and A(:,j) is in a slide XX(1,:,j) before SQUEEZE is invoked.

The squeeze command removes the 1st singleton dimension, so XX(:,j) is common 1-values of B and A(:,j).

NOTE: You might transpose the result so each row corresponds to result of a column of A with you prefer.

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