perl: $#

I was confused by some perl tutorials/books that claim you can use $# to get the size of an array.

Actually $# returns the last index of the array. The things can be messed with $[, special perl variable that stands for the index of the first element in an array.
But if environment haven't been modified $# will return 'size of the array' - 1.

To get amount of elements the array should be used in scalar context or using scalar function.

Please, don't use $# to get the amount of the elements in the array. You may confuse your followers and yourself.