Operator Input Forms

Characters that are not letters, letterlike forms, or structural elements are treated by the Wolfram Language as operators. The Wolfram Language has builtin rules for interpreting all operators. The functions to which these operators correspond may or may not, however, have builtin evaluation or other rules. Cases in which builtin meanings are by default defined are indicated by in the tables below.

Operators that construct twodimensional boxesall of which have names beginning with backslashcan only be used inside \(\). The table below gives the interpretations of these operators within . "Input of Boxes" gives interpretations when no is included.

exprandexpriany expression
symbany symbol
pattany pattern object
stringandstringi or a sequence of letters, letterlike forms, and digits
filenamelike string, but can include additional characters described below
builtin meanings exist

Objects used in the tables of operator input forms.

Operator Precedence

operator form
full form
grouping
forms representing numbers (see Numbers)
forms representing symbols (see Symbol Names and Contexts)
forms representing character strings (see Character Strings)
e11e12
e21e22
{{e11,e12,},{e21,e22,},}
e11e12
e21e22
Piecewise[{{e11,e12},{e21,e22},}]
expr::stringMessageName[expr,"string"]
expr::string1::string2MessageName[expr,"string1","string2"]
forms containing (see additional input forms)
forms containing (see additional input forms)
forms containing (see additional input forms)
<<filenameGet["filename"]
Overscript[expr1,expr2]
expr1\&expr2Overscript[expr1,expr2]e\&(e\&e)
Underscript[expr1,expr2]
expr1\+expr2Underscript[expr1,expr2]e\+(e\+e)
Underoverscript[expr1,expr2,expr3]
expr1\+expr2\%expr3Underoverscript[expr1,expr2,expr3]
expr1\&expr2\%expr3Underoverscript[expr1,expr3,expr2]
expr1expr2Subscript[expr1,expr2]e(ee)
expr1\_expr2Subscript[expr1,expr2]e\_(e\_e)
expr1\_expr2\%expr3Power[Subscript[expr1,expr2],expr3]
\!boxes(interpreted version of boxes)
expr1?expr2PatternTest[expr1,expr2]
expr1[expr2,]expr1[expr2,](e[e])[e]
expr1[[expr2,]]Part[expr1,expr2,](e[[e]])[[e]]
expr1expr2,Part[expr1,expr2,](ee)e
expr1expr2Part[expr1,expr2,](ee)e
\*expr(boxes constructed from expr)
expr++Increment[expr]
expr--Decrement[expr]
++exprPreIncrement[expr]
--exprPreDecrement[expr]
expr1@*expr2Composition[expr1,expr2]e@*e@*e
expr1/*expr2RightComposition[expr1,expr2]e/*e/*e
expr1@expr2expr1[expr2]e@(e@e)
expr1 expr2(invisible application, input as Esc@Esc )
expr1[expr2]
expr1~expr2~expr3expr2[expr1,expr3](e~e~e)~e~e
expr1/@expr2Map[expr1,expr2]e/@(e/@e)
expr1//@expr2MapAll[expr1,expr2]e//@(e//@e)
expr1@@expr2Apply[expr1,expr2]e@@(e@@e)
expr1@@@expr2Apply[expr1,expr2,{1}]e@@@(e@@@e)
expr!Factorial[expr]
expr!!Factorial2[expr]
exprConjugate[expr]
exprTranspose[expr]
exprConjugateTranspose[expr]
exprConjugateTranspose[expr]
expr'Derivative[1][expr]
expr''' (n times)Derivative[n][expr]
expr1<>expr2<>expr3StringJoin[expr1,expr2,expr3]e<>e<>e
expr1^expr2Power[expr1,expr2]e^(e^e)
expr1expr2Power[expr1,expr2]e(ee)
Power[Subscript[expr1,expr2],expr3]
expr1\^expr2\%expr3Power[Subscript[expr1,expr3],expr2]
vertical arrow and vector operators
Sqrt[expr]
\@ exprSqrt[expr]\@(\@ e)
\@ expr\%nPower[expr,1/n]
expr1 expr2Integrate[expr1,expr2] ( e e) e
e3e4Integrate[e3,{e4,e1,e2}] ( e e) e
other integration operators
expr1expr2D[expr2,expr1]e(ee)
exprDel[expr](e)
expr1expr2DiscreteShift[expr2,expr1]e(ee)
expr1expr2DiscreteRatio[expr2,expr1]e(ee)
expr1expr2DifferenceDelta[expr2,expr1]e(ee)
exprSquare[expr]( e)
expr1 expr2 expr3SmallCircle[expr1,expr2,expr3]e e e
expr1 expr2 expr3CircleDot[expr1,expr2,expr3]e e e
expr1**expr2**expr3NonCommutativeMultiply[expr1,expr2,expr3]e**e**e
expr1expr2expr3Cross[expr1,expr2,expr3]eee
expr1.expr2.expr3Dot[expr1,expr2,expr3]e.e.e
-exprTimes[-1,expr]
+exprexpr
±exprPlusMinus[expr]
exprMinusPlus[expr]
expr1/expr2expr1(expr2)^-1(e/e)/e
expr1÷expr2Divide[expr1,expr2](e÷e)÷e
expr1\/expr2Divide[expr1,expr2](e\/e)\/e
expr1expr2expr3Backslash[expr1,expr2,expr3]eee
expr1expr2expr3Diamond[expr1,expr2,expr3]eee
expr1expr2expr3Wedge[expr1,expr2,expr3]eee
expr1expr2expr3Vee[expr1,expr2,expr3]eee
expr1expr2expr3CircleTimes[expr1,expr2,expr3]eee
expr1·expr2·expr3CenterDot[expr1,expr2,expr3]e·e·e
expr1 expr2 expr3Times[expr1,expr2,expr3]e e e
expr1*expr2*expr3Times[expr1,expr2,expr3]e*e*e
expr1×expr2×expr3Times[expr1,expr2,expr3]e×e×e
expr1expr2expr3Star[expr1,expr2,expr3]eee
e4Product[e4,{e1,e2,e3}]( e)
expr1expr2expr3VerticalTilde[expr1,expr2,expr3]eee
expr1expr2expr3Coproduct[expr1,expr2,expr3]eee
expr1expr2expr3Cap[expr1,expr2,expr3]eee
expr1expr2expr3Cup[expr1,expr2,expr3]eee
expr1 expr2 expr3CirclePlus[expr1,expr2,expr3]eee
expr1 expr2CircleMinus[expr1,expr2](e e) e
e4Sum[e4,{e1,e2,e3}]( e)
expr1+expr2+expr3Plus[expr1,expr2,expr3]e+e+e
expr1-expr2expr1+(-1expr2)(e-e)-e
expr1±expr2PlusMinus[expr1,expr2](e±e)±e
expr1expr2MinusPlus[expr1,expr2](ee)e
expr1expr2Intersection[expr1,expr2]eee
other intersection operators
expr1expr2Union[expr1,expr2]eee
other union operators
i;;j;;kSpan[i,j,k]e;;e;;e
expr1==expr2Equal[expr1,expr2]e==e==e
expr1==expr2Equal[expr1,expr2]e==e==e
expr1expr2Equal[expr1,expr2]eee
expr1!= expr2Unequal[expr1,expr2]e!=e!=e
expr1!=expr2Unequal[expr1,expr2]e!=e!=e
other equality and similarity operators
expr1>expr2Greater[expr1,expr2]e>e>e
expr1>=expr2GreaterEqual[expr1,expr2]e>=e>=e
expr1expr2GreaterEqual[expr1,expr2]eee
expr1expr2GreaterEqual[expr1,expr2]eee
expr1<expr2Less[expr1,expr2]e<e<e
expr1<=expr2LessEqual[expr1,expr2]e<=e<=e
expr1expr2LessEqual[expr1,expr2]eee
expr1expr2LessEqual[expr1,expr2]eee
other ordering operators
expr1expr2VerticalBar[expr1,expr2]eee
expr1expr2NotVerticalBar[expr1,expr2]eee
expr1expr2DoubleVerticalBar[expr1,expr2]eee
expr1expr2NotDoubleVerticalBar[expr1,expr2]eee
horizontal arrow and vector operators
diagonal arrow operators
expr1===expr2SameQ[expr1,expr2]e===e===e
expr1=!=expr2UnsameQ[expr1,expr2]e=!=e=!=e
expr1expr2Element[expr1,expr2]eee
expr1expr2NotElement[expr1,expr2]eee
expr1expr2Subset[expr1,expr2]eee
expr1expr2Superset[expr1,expr2]eee
other set relation operators
expr1expr2ForAll[expr1,expr2]e(ee)
expr1expr2Exists[expr1,expr2]e(ee)
expr1expr2NotExists[expr1,expr2]e(ee)
!exprNot[expr]!(!e)
¬exprNot[expr]¬(¬e)
expr1&&expr2&&expr3And[expr1,expr2,expr3]e&&e&&e
expr1expr2expr3And[expr1,expr2,expr3]eee
expr1expr2expr3Nand[expr1,expr2,expr3]eee
expr1expr2expr3Xor[expr1,expr2,expr3]eee
expr1expr2expr3Xnor[expr1,expr2,expr3]eee
expr1||expr2||expr3Or[expr1,expr2,expr3]e||e||e
expr1expr2expr3Or[expr1,expr2,expr3]eee
expr1expr2expr3Nor[expr1,expr2,expr3]eee
expr1expr2expr3Equivalent[expr1,expr2,expr3]eee
expr1expr2Implies[expr1,expr2]e(ee)
expr1expr2Implies[expr1,expr2]eee
expr1expr2RightTee[expr1,expr2]e(ee)
expr1expr2DoubleRightTee[expr1,expr2]e(ee)
expr1expr2LeftTee[expr1,expr2](ee)e
expr1expr2DoubleLeftTee[expr1,expr2](ee)e
expr1expr2UpTee[expr1,expr2](ee)e
expr1expr2DownTee[expr1,expr2](ee)e
expr1expr2SuchThat[expr1,expr2]e(ee)
expr..Repeated[expr]
expr...RepeatedNull[expr]
expr1|expr2Alternatives[expr1,expr2]e|e|e
symb:exprPattern[symb,expr]
patt:exprOptional[patt,expr]
expr1~~expr2~~expr3StringExpression[expr1,expr2,expr3]e~~e~~e
expr1/;expr2Condition[expr1,expr2](e/;e)/;e
expr1->expr2Rule[expr1,expr2]e->(e->e)
expr1expr2Rule[expr1,expr2]e(ee)
expr1:>expr2RuleDelayed[expr1,expr2]e:>(e:>e)
expr1 expr2RuleDelayed[expr1,expr2]e(ee)
expr1/.expr2ReplaceAll[expr1,expr2](e/.e)/.e
expr1//.expr2ReplaceRepeated[expr1,expr2](e//.e)//.e
expr1+=expr2AddTo[expr1,expr2]e+=(e+=e)
expr1-=expr2SubtractFrom[expr1,expr2]e-=(e-=e)
expr1*=expr2TimesBy[expr1,expr2]e*=(e*=e)
expr1/=expr2DivideBy[expr1,expr2]e/=(e/=e)
expr&Function[expr]
expr1expr2Colon[expr1:expr2]eee
expr1//expr2expr2[expr1](e//e)//e
expr1expr2VerticalSeparator[expr1,expr2]eee
expr1expr2Therefore[expr1,expr2]e(ee)
expr1expr2Because[expr1,expr2](ee)e
expr1=expr2Set[expr1,expr2]e=(e=e)
expr1:=expr2SetDelayed[expr1,expr2]e:=(e:=e)
expr1^=expr2UpSet[expr1,expr2]e^=(e^=e)
expr1^:=expr2UpSetDelayed[expr1,expr2]e^:=(e^:=e)
symb/:expr1=expr2TagSet[symb,expr1,expr2]
symb/:expr1:=expr2TagSetDelayed[symb,expr1,expr2]
expr=.Unset[expr]
symb/:expr=.TagUnset[symb,expr]
expr1expr2Function[{expr1},expr2]e(ee)
expr>>filenamePut[expr,"filename"]
expr>>>filenamePutAppend[expr,"filename"]
expr1;expr2;expr3CompoundExpression[expr1,expr2,expr3]
expr1;expr2;CompoundExpression[expr1,expr2,Null]
expr1\`expr2FormBox[expr2,expr1]e\`(e\`e)

Operator input forms, in order of decreasing precedence.

special input form
full form
#Slot[1]
#nSlot[n]
#stringSlot["string"]
##SlotSequence[1]
SlotSequence[n]
%Out[ ]
%%Out[-2]
%%% (n times)Out[-n]
%nOut[n]
_Blank[ ]
_exprBlank[expr]
__BlankSequence[ ]
__exprBlankSequence[expr]
___BlankNullSequence[ ]
___exprBlankNullSequence[expr]
_.Optional[Blank[ ]]
symb_Pattern[symb,Blank[ ]]
symb_exprPattern[symb,Blank[expr]]
symb__Pattern[symb,BlankSequence[ ]]
symb__exprPattern[symb,BlankSequence[expr]]
symb___Pattern[symb,BlankNullSequence[ ]]
symb___exprPattern[symb,BlankNullSequence[expr]]
symb_.Optional[Pattern[symb,Blank[ ]]]

Additional input forms, in order of decreasing precedence.

Special Characters

Special characters that appear in operators usually have names that correspond to the names of the functions they represent. Thus the character has the name \[CirclePlus] and yields the function CirclePlus. Exceptions are \[GreaterSlantEqual], \[LessSlantEqual] and \[RoundImplies].

The delimiters in matchfix operators have names and .

"Listing of Named Characters" gives a complete listing of special characters that appear in operators.

keyboard characters
special character
->\[Rule]
:>\[RuleDelayed]
==\[Equal]
!=\[NotEqual]
keyboard characters
special character
>=\[GreaterEqual]
>=\[GreaterSlantEqual]
<=\[LessEqual]
<=\[LessSlantEqual]

Keyboard and special characters with the same interpretations.

Some keyboard and special characters with different interpretations.

Precedence and the Ordering of Input Forms

The tables of input forms are arranged in decreasing order of precedence. Input forms in the same box have the same precedence. Each page in the table begins a new box. As discussed in "Special Ways to Input Expressions", precedence determines how the Wolfram Language groups terms in input expressions. The general rule is that if has higher precedence than , then is interpreted as , and is interpreted as .

Grouping of Input Forms

The third columns in the tables show how multiple occurrences of a single input form, or of several input forms with the same precedence, are grouped. For example, is grouped as ("left associative"), while is grouped as ("right associative"). No grouping is needed in an expression like , since Plus is fully associative, as represented by the attribute Flat.

Precedence of Integration Operators

Forms such as have an "outer" precedence just below Power, as indicated in the table above, but an "inner" precedence just above . The outer precedence determines when needs to be parenthesized; the inner precedence determines when needs to be parenthesized.

\[ContourIntegral], \[ClockwiseContourIntegral] and \[DoubleContourIntegral] work the same as \[Integral].

See "Two-Dimensional Input Forms" for twodimensional input forms associated with integration operators.

Spaces and Multiplication

Spaces in the Wolfram Language denote multiplication, just as they do in standard mathematical notation. In addition, the Wolfram Language takes complete expressions that are adjacent, not necessarily separated by spaces, to be multiplied together.

x y z x*y*z
2x 2*x
2(x+1) 2*(x+1)
c(x+1) c*(x+1)
(x+1)(y+2) (x+1)*(y+2)
x! y x!*y
x!y x!*y

Alternative forms for multiplication.

An expression like could potentially mean either or . The first interpretation is chosen because Factorial has higher precedence than Not.

Spaces within single input forms are ignored. Thus, for example, is equivalent to . You will often want to insert spaces around lower precedence operators to improve readability.

You can give a "coefficient" for a symbol by preceding it with any sequence of digits. When you use numbers in bases larger than 10, the digits can include letters. (In bases other than 10, there must be a space between the end of the coefficient and the beginning of the symbol name.)

, like , means
, like , means
is a single symbol, not

Some cases to be careful about.

Spaces to Avoid

You should avoid inserting any spaces between the different characters in composite operators such as , , and . Although in some cases such spaces are allowed, they are liable to lead to confusion.

Another case where spaces must be avoided is between the characters of the pattern object . If you type , the Wolfram Language will interpret this as , rather than the single named pattern object .

Similarly, you should not insert any spaces inside pattern objects like .

Spacing Characters

Spacing characters equivalent to an ordinary keyboard space.

Relational Operators

Relational operators can be mixed. An expression like is converted to Inequality[a,Greater,b,GreaterEqual,c], which effectively evaluates as . (The reason for the intermediate form is that it prevents objects from being evaluated twice when input like is processed.)

File Names

Any file name can be given in quotes after , , and . File names can also be given without quotes if they contain only alphanumeric characters, special characters, and the characters , , , , , , , , , , , and , together with matched pairs of square brackets enclosing any characters other than spaces, tabs, and newlines. Note that file names given without quotes can be followed only by spaces, tabs, or newlines, or by the characters , , or , as well as semicolons and commas.