? -- comparison operator

Synopsis

Usage:

x ? y
Inputs:
- x
- y
Outputs:
- One of the symbols symbol <, symbol >, symbol ==, or incomparable, depending (respectively) on whether x < y, x > y, x == y, or x and y are not comparable.

Description

Many types of objects may be compared. Numbers are handled as one would expect, and strings, lists and sequences are generally compared lexicographically.

i1 : 3 ? 4

o1 = <

o1 : Keyword

i2 : "book" ? "boolean"

o2 = <

o2 : Keyword

i3 : 3 ? 3.

o3 = ==

o3 : Keyword

i4 : {1,2,3} ? {4,5}

o4 = <

o4 : Keyword

Polynomials from the same ring may also be compared. The order depends on the monomial order in the ring.

i5 : R = ZZ[a,b,c]

o5 = R

o5 : PolynomialRing

i6 : a*c ? b^2

o6 = <

o6 : Keyword

A set is smaller than another if it is a subset; for tallies, corresponding counts should all be smaller.

i7 : set {1,2} ? set {2,3}

o7 = incomparable

o7 : Symbol

i8 : set {1,2} ? set {1,2,3}

o8 = <

o8 : Keyword

i9 : tally {1,1,2} ? tally {1,2,3}

o9 = incomparable

o9 : Symbol

i10 : tally {1,1,2} ? tally {1,1,2,3}

o10 = <

o10 : Keyword

Ways to use symbol ? :

IndexedVariable ? IndexedVariable
List ? List
Symbol ? IndexedVariable
VirtualTally ? VirtualTally
? Command (missing documentation)
? Function -- see ? Symbol -- view brief documentation of a symbol
? Keyword -- see ? Symbol -- view brief documentation of a symbol
? Package -- see ? Symbol -- view brief documentation of a symbol
? ScriptedFunctor -- see ? Symbol -- view brief documentation of a symbol
? Symbol -- view brief documentation of a symbol
? Type -- see ? Symbol -- view brief documentation of a symbol
Bag ? Bag -- see Bag -- the class of all bags
CC ? InfiniteNumber (missing documentation)
Constant ? Constant (missing documentation)
Constant ? Number (missing documentation)
InexactNumber ? Constant (missing documentation)
InfiniteNumber ? CC (missing documentation)
InfiniteNumber ? RR (missing documentation)
Module ? Module (missing documentation)
MonoidElement ? MonoidElement (missing documentation)
Number ? Constant (missing documentation)
Option ? Option (missing documentation)
RR ? InfiniteNumber (missing documentation)
VirtualTally ? ZZ (missing documentation)
ZZ ? VirtualTally (missing documentation)

For the programmer

The object ? is a keyword.

This operator may be used as a binary operator in an expression like x?y. The user may install binary methods for handling such expressions with code such as

         X ? Y := (x,y) -> ...

where X is the class of x and Y is the class of y.

This operator may be used as a prefix unary operator in an expression like ?y. The user may install a method for handling such expressions with code such as

           ? Y := (y) -> ...

where Y is the class of y.

? -- comparison operator

Synopsis

Description

See also

Ways to use symbol ? :

For the programmer