expr[[i]] or Part[expr, i] gives the i\[Null]^th part of expr. expr[[-i]] counts from the end. expr[[i, j, ...]] or Part[expr, i, j, ...] is equivalent to expr[[i]][[j]] .... ...

NumberQ[expr] gives True if expr is a number, and False otherwise.

The functionality of PrimitiveElement is now available in the newly added built-in Mathematica kernel function ToNumberField.

Most[expr] gives expr with the last element removed.

Tuples[list, n] generates a list of all possible n-tuples of elements from list. Tuples[{list_1, list_2, ...}] generates a list of all possible tuples whose i\[Null] ...

Uncompress["string"] recovers an expression from a compressed string representation generated by Compress.Uncompress["string", h] wraps the head h around the expression ...

Mathematica provides functions that allow users to write their own file format converters and integrate them with the Mathematica Import and Export framework. You can ...

Specifying patterns that involve alternatives. This defines h to give p when its argument is either a or b. The first two cases give p.

EndModal[] is the head of an expression sent by Java to signal the end of a DoModal[] loop.

LeafCount[expr] gives the total number of indivisible subexpressions in expr.