Mathematica pseudo-types Integer, Real, Rational, Complex, String and Symbol, and their use.
Although Mathematica is in many ways an untyped language, there are standard "heads" (as revealed by the function
Head) that are characteristic of and used throughout the system. Among these are "atomic" heads that may be considered analogous to types. These include:
Complex for numeric data, as well as
Integer data can be stored in packed-arrays.
True | False can be given to