"if i try to print the result of my software, what i obtain is the printing of all table or the printing of all column without the possibility of printing only one cell (and manipulate it)"

In the link I gave you the code either prints or manipulates before using the value of stored within <td> tags. Did you look at this?

"I will start study Mojo::DOM, why do you think is the best solution?"

I didn't say it was the best solution, but it makes dealing with data like this trivial, even for complex selectors (the example previously given has details of a reasonable complex selector).