Wolfram Language Syntax
The Wolfram Language has a rich syntax carefully designed for consistency and efficient, readable entry of the Wolfram Language's many language, mathematical, and other constructs. In addition to ordinary linear ASCII input, the Wolfram Language also supports full 2D mathematical input.
Basic Syntax
f[x,y] — function arguments go in square brackets
Exp, Do, ... — built-in symbols have names beginning with capital letters
{…} (List) ▪ <|…|> (Association) ▪ "…" (String) ▪ e[[i]] (Part) ▪ e[[i;;j]] (Span)
Basic Operations
x = val — set a value (=. to clear a value)
x == val — test equality or represent a symbolic equation (!= for unequal)
lhs := rhs — function etc. definition
a -> b, a b — rule for transformations, options, etc. (:> for delayed rule)
expr /. rule — replace using a rule ("slash dot")
Mathematics & Operators
+ ▪ - ▪ * ▪ / ▪ ^ (Power) ▪ && (And) ▪ || (Or) ▪ ! (Not) ▪ <> (StringJoin)
a b c — spaces stand for multiplication
∈ (Element) ▪ (Distributed) ▪ (UndirectedEdge) ▪ (DirectedEdge)
Patterns
x_ — any expression ("x blank")
x__, x___ — sequences of arbitrary expressions ("x double blank", ...)
x:p — pattern name
p:d — pattern default
.. (Repeated) ▪ | (Alternatives) ▪ /; (Condition) ▪ ? (PatternTest)
~~ (StringExpression) — concatenation of string patterns
Pure Functions
body&, x|->body, xbody— a pure function
#, #2, etc. — unnamed arguments in a pure function
#name — named part of a pure function argument
Function Combinations
f@*g — composition of f with g (f[g[…]])
f/*g — composition of g with f (g[f[…])
Short Forms
f @ expr — prefix function application f[expr]
expr // f — postfix function application ("slash slash") f[expr]
/@ (Map — "slash at" ) ▪ @@(Apply) ▪ @@@ (MapApply) ▪ //= (ApplyTo) ▪ === (SameQ)
Program Syntax
expr; expr; expr — sequence of commands (CompoundExpression)
<< file — input a file (>>file, >>>file for outputting to a file)
ccc`nnn — symbol in context ccc
Session Syntax
% — most recent output (%n for output on line n)
? x — information on symbol 