extract array from a matrix

I need to extract the arrays from a tab that contain an assigned value for instance on the Matrix A take all the rows with contain the value 10 on the first column How Can I Do???

Answer 1

[Christian Heigele]

Logical indexing:

 A(A(:,1)==10,:)

That states which rows you want to select: A(:,1)==10 , with A(cond, :) you access all those who are selected.

[ADC]

very usefull but it doesn't work if for exsample I've the needed to import data like a table...

I got an error when put the operator ==, is there any other way to do it???