How to extract value from some row or column in a matrix

Dear members

I have two matrix

A is a matrix that has 100 row=[1 2 3 4 5 6 7 8 9 10 ......100]

B is a matrix that wants to get the value from row 1 to row 10, and from row 25 to row 35

How to get matrix B

Thank you

[Image Analyst]

Terminology note: your A is a special kind of matrix called a "row vector" since it is a horizontal list of 100 numbers. It has 100 columns, not 100 rows. It has only one row.

So not exactly sure what you have, but madhan gives several options to choose from below in his answer, depending on what you have.

Answer 1

[madhan ravi]

By indexing like shown below:

% if A is a matrix
A=rand(100); % fake data
B=A([1:10 25:35],:) % extracts specified rows
B=A(:,[1:10 25:35]) % extracts specified columns
% if A is a vector then
A=1:100; % fake data (row vector) , (1:100).' - column vector
B=A([1:10 25:35]) % extracts specified elements (1D-a vector)

Note: The square brackets [] is used to denote discontinuities thereby extracting the spcified elements, rows or columns.

See https://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html for better understanding.

[madhan ravi]

If it’s not what you are looking for give some explanation on what you are trying to achieve.

[Tran Hoa]

Thank you very much. It works well

[madhan ravi]

Anytime :)

[Afluo Raoual]

Thank you. It help