Mathematica symbolic expressions can represent an immense range of types of objects.
Mathematica provides a rich collection of functions to test expressions. Functions that "ask a question" have names that end in Q. They return
True for an explicit true answer, and
False otherwise.
SameQ (
===),
UnsameQ (
=!=) — literal symbolic identity
NumberQ,
MachineNumberQ — literal number, literal machine-precision number
NumericQ — numeric quantity (consisting of numbers, numeric constants, and functions)
VectorQ,
MatrixQ — vector, matrix, perhaps with elements of specified types
MemberQ — test whether a pattern occurs in a list
MatchQ — test whether an expression matches a pattern
