MATLAB: Get specific elements from matrix

matrix manipulation

Hello,

From an arbitrary matrix I want to extract n elements when I have 2 arrays of lenth n, one containing the row indices and 1 containing the column indices of the desired elements.

For effeciency I would like to avoid a for loop. Is this possible?

Thanks!

Best Answer

YourMatrix( sub2ind( size(YourMatrix), Rows, Columns ) )

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MATLAB: How could I extract all the row and column of the matrix if elements of matrix satisfies certain conditions

Try this:

if someCondition
   allRowsAndColumns = YourMatrix;
end

Seriously, that's about all we can say given what you've told us.

MATLAB: How do you turn a 30x30x24 matrix into a 24×900 matrix

Well, you could

reshape(YourMatrix, size(YourMatrix,3), [])

but it is quite unlikely that is what you want. You probably want

reshape(permute(YourMatrix, [3 1 2]), size(YourMatrix,3), [])

This would take each original 30 x 30 plane of numbers and make it into a row.

Best Answer

Related Solutions

MATLAB: How could I extract all the row and column of the matrix if elements of matrix satisfies certain conditions

MATLAB: How do you turn a 30x30x24 matrix into a 24×900 matrix

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