What does the dubled squarebrackets at line 10 do? How do they work?

Question

https://code.sololearn.com/cMVr292O6zOy/?ref=app

Answer 1

It's a multidimensional array. In this case it's a 2D array. Each [] is referencing the index. In a 2D array, you can think of it as rows/columns or a coordinate system.

myArray[row][col]

Answer 2

To access the element inside the list which is inside another list, first set of square brackets select the list the second set select the element

Answer 3

Thx you two TurtleShell and Jakob Marley . Very helpfull!