Delete values in the array

Question

Conrado Dias 2015-4-11

编辑： Stephen23 2015-4-13

I'm having trouble developing a script. The problem:

In a matrix with positive and negative numbers, delete the values "greater and equal" and "smaller and equal" a certain value. Example:

Delete values above 100 and below -100

if anyone can help.

Thanks.

Answer 1

Stephen23 2015-4-11

编辑：Stephen23 2015-4-13

Deleting single elements from a matrix does not really make much sense. Lets have a look at a simple case:

>> A = [1,2;3,101;4,5]
A =
   1     2
   3   101
   4     5

If we try to delete the element > 100, then we end up with something that is not a matrix, and cannot be stored in MATLAB:

   2
      <- what happens here?
   5

So what can we do instead of creating that empty space? The answer is one of two things:

1. Replace the value with another value, e.g. zero or NaN:

>> A(A>100) = NaN
A =
   1     2
   3   NaN
   4     5

2. Delete an entire row or column, e.g. here I delete the whole second row:

>> X = any(A>100,2)
X =
   0
   1
   0
>> A(X,:) = []
A =
   1     2
   4     5

Conrado Dias 2015-4-13

Thank you, was of great help.