Slices represent variable-length sequences
whose elements all have the same type.
A slice type is written
T, where the elements have
T; it looks like an array type without a size.
Arrays and slices are intimately connected. A slice is a lightweight data structure that gives access to a subsequence (or perhaps all) of the elements of an array, which is known as the slice’s underlying array. A slice has three components: a pointer, a length, and a capacity. The pointer points to the first element of the array that is reachable through the slice, which is not necessarily the array’s first element. The length is the number of slice elements; it can’t exceed the capacity, which is usually the number of elements between the start ...