take values from old matrix to newer

hello

i got from a code matrix A in size 28281X5.

at colums 3, 4 and 5 there are negetive varibles.

i want to creat a new matrix from A matrix that include all the lines from A matrix withuot the lines with the

negative varibles

thanks for the help !

Tal

Answer 1

[Star Strider]

Create the output matrix ‘B’ as:

B = A(all(A(:,3:5) >= 0, 2),:)                              % Result

Example—

A = [randi(9, 15, 2)  randi([-4 +5], 15, 3)]                % Create ‘A’
B = A(all(A(:,3:5) >= 0, 2),:)                              % Result

[tal shmuel]

what the meaning of the number 2 after A(:,3:5) >= 0 ?

[Star Strider]

That is an argument to the all function:

all(A(:,3:5) >= 0, 2)

It tells all to calculate the logic across columns (that is, across each row, dimension 2) rather than down the columns (that would be dimension 1). These are MATLAB dimension conventions for 2D arrays.

[tal shmuel]

thank you !!

[Star Strider]

My pleasure!

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