Can anyone explain this array declaration to me?

Question

Hi guys, just wondering the difference between the presence of the last comma in the array, if there is any at all

>> [1,2,3]
=> [1, 2, 3]

>> [1,2,3,]
=> [1, 2, 3]

The second array still works, no exception raised

Thanks

Answer 1

There's no difference. In Ruby, you're free to add a trailing comma to an array. It makes syntax like this:

a = [
  1,
  2,
  3,
]

A bit nicer, in some cases (e.g., if you want to add an element, you simply add a 4, line and don't have to worry about checking for a comma on the last line).

Answer 2

It isn't a error, just a empty value(ignored by the compiler), but I suggest you to read Understanding Ruby Arrays