Question

Getting confused by syntax here, but what is the difference between:

foo[x][y] 

and

foo[x, y]

Answer 1

• foo[x, n] returns n elements from foo starting from the xth element.
• foo[x][y] finds the xth element in foo and returns its yth element.

Here’s an example to demonstrate:

> foo = [[0,1,2],[3,4,5],[6,7,8],[9,10,11],[12,13,14]]
=> [[0, 1, 2], [3, 4, 5], [6, 7, 8], [9, 10, 11], [12, 13, 14]]
> foo[1,2]
=> [[3, 4, 5], [6, 7, 8]]
> foo[1][2]
=> 5