This is documentation for Mathematica 7, which was
based on an earlier version of the Wolfram Language.
 Assignments Mathematica's symbolic architecture supports a highly generalized notion of assignment, in which you can specify a transformation for any class of expressions defined by a Mathematica pattern. Simple cases correspond to assignments for "variables", "indexed variables" or "structure elements". Other cases define functions or general transformations. x=v — assign a value (Set) {x,y}={u,v} — assign multiple values {x,y}={y,x} — swap values      a[[i]]=v — assign a value to a list/array/expression element      x++ (Increment)  ▪ ++x (PreIncrement)  ▪ x+=y (AddTo) x-- (Decrement)  ▪ --x (PreDecrement)  ▪ x-=y (SubtractFrom) x*=y (TimesBy)  ▪ x/=y (DivideBy) AppendTo, PrependTo — add elements to a list      Function Definitions f[x_]:=body — define a function      Forms of Assignment lhs=rhs — immediate assignment, with rhs evaluated at the time of assignment lhs:=rhs — delayed assignment, with rhs reevaluated every time it is used      f/:lhs=rhs, f/:lhs:=rhs — associate assignments with the head f lhs^=rhs, lhs^:=rhs — define "upvalues" associated with the leading head in lhs      Clearing Assignments x=. — unset the value of x (Unset) Clear — clear all values associated with a symbol      Information about Assignments ?x (Information) — get information about all assignments for x TUTORIALS Associating Definitions with Different Symbols Making Definitions Defining Variables Defining Numerical Values Defining Functions Making Definitions for Functions Immediate and Delayed Definitions MORE ABOUT Variables and Functions RELATED LINKS How to: Work with Variables and Functions