Extracting values from one column by specifying range for two other columns

Hi, I have a 556*4 matrix. I want to extract/display values from column 1 when -32.5<=x<=40 and 54.5<=y<=62.5 where x and y are 3rd and 4th column values of the same matrix. How can I do this? Other than using for and if loop, is there any other way?

If this is very basic question, then please tell which tutorial or manual should I refer to?

Answer 1

[David Young]

Using A to refer to your matrix, try

x = A(:, 3);
y = A(:, 4);
ok = -32.5 <= x & x <= 40 & 54.5 <= y & y <= 62.5;
results = A(ok, 1);

For documentation, give the command

doc

and in the help window look at MATLAB > Language Fundamentals > Matrices and Arrays

[Venkatesh M Deshpande]

thanks. this really works well. However, I am not able to understand how "ok" is working. In workspace, ok is seen as logical. What is the data type of ok?

[David Young]

Yes, ok is logical. It has a true value in every row where the inequalities are all satisfied, and a false value in the other rows. When used as an index, only the rows with true values in ok are selected.

[Venkatesh M Deshpande]

ok, thank you.