At
The element at the given position; a negative index counts from the end.
Wolfram Language
Part!At(collection, index)the element at `index`; a negative index counts from the end.At(collection, [i1, i2, …])the elements at several positions at once.At(collection, Range(start, end))a contiguous slice selected by a Range.Details
- Negative indices count from the end:
is the last element. See Last. - Chaining reaches into nested collections, like indexing a matrix row then column.
- An out-of-range index evaluates to
rather than raising an error. - compute-engine treats 0 as out of range.
- Positional element access, 1-based; negative indices count from the end.