conditionally deleting matrix rows

Hi all,

I wish to delete matrix rows according to a condition imposed over its columns. let assume the matrix is of 10x2 (rows x columns) size.

A= [16 45; 79 8; 31 23; 53 91; 17 15; 60 83; 26 54; 65 100; 69 8; 75 44]

I want to delete the row if either A(i,1) or A(i,2) is larger than 50

A= [16 45; 31 23; 17 15]

Answer 1

[Image Analyst]

Try this:

A= [16 45; 79 8; 31 23; 53 91; 17 15; 60 83; 26 54; 65 100; 69 8; 75 44]
rowsToDelete = any(A>50, 2)
A(rowsToDelete,:) = []

[Abdelwahab Fawzy]

thanks a lot for this great answer,

what about ... if the condition (A>50 or A<30)

[Image Analyst]

rowsToDelete = any(A>50 | A<30, 2)

[Romain Hautier]

Hello,

I know it has been a long time since you answered but I have an additional question. Is it possible to delete rows and colums satisfying a condition all at once? Say I have a matrix A = [1 2 3; 3 0 0; 1 2 0], would I be able to delete all rows and columns containing a 0 all at once to be left with A = [1]?

Thank you in advance.

[Image Analyst]

A = [1 2 3; 3 0 0; 1 2 0]

A = 3×3

1 2 3 3 0 0 1 2 0

rowsToDelete = any(A == 0, 2)

rowsToDelete = 3×1 logical array
   0
   1
   1

columnsToDelete = any(A == 0, 1)

columnsToDelete = 1×3 logical array
   0   1   1

A(rowsToDelete, :) = [];
A(:, columnsToDelete) = []

A = 1