How can pick a specific values (rows,columns) from a matrix?

Hi all,

I want to process a part of large a matrix. Let's assume we have a matrix with 10 rows and 10 columns, I want to pick a small matrix from it with 4 rows and 5 columns. How can I do it?

Thank you

Answer 1

[Nick]

if a = rand(10,10)

if you want 4 rows and 5 columns you can do a([1:4],[1:5]) and it will give you the first 4 rows and 5 columns. a([4:7],[5:9]) will give you rows 4-7 and columns 5-9 etc.

Answer 2

[Nani Venky]

Previous answers are applicable if you want to select consecutive rows or columns.The below way can be used to select elements from any row and column.

Example:

A = randi(10,6,6);

B = A([1:2 4:end],[1:2 5:end]);

This way you can form a matrix B that contains the element in A except from third row and third and fourth columns.