Testing Expressions

Mathematica symbolic expressions can represent an immense range of types of objects. Mathematica provides a rich collection of functions to test expressions. Functions that "ask a question" have names that end in Q. They return True for an explicit true answer, and False otherwise.

ReferenceReference

Equality & Inequality

Equal (==), Unequal (!=) — numerical equality

SameQ (===), UnsameQ (=!=) — literal symbolic identity

Less(<) ▪ Greater(>) ▪ LessEqual(<=) ▪ GreaterEqual(>=)

Logical Combinations »

And(&&) ▪ Or(||) ▪ Not(!) ▪ True ▪ False ▪ ...

Numerical Properties »

NumberQ, MachineNumberQ literal number, literal machine-precision number

NumericQ numeric quantity (consisting of numbers, numeric constants, and functions)

IntegerQ ▪ EvenQ ▪ OddQ ▪ PrimeQ ▪ CoprimeQ ▪ AlgebraicIntegerQ ▪ ...

Positive ▪ Negative ▪ NonPositive ▪ NonNegative ▪ PossibleZeroQ

List-Oriented Tests

VectorQ, MatrixQ vector, matrix, perhaps with elements of specified types

ArrayQ full array of any depth

MemberQ test whether a pattern occurs in a list

Expression Tests

MatchQ test whether an expression matches a pattern

AtomQ ▪ TrueQ ▪ OrderedQ ▪ PolynomialQ

String Tests »

StringQ ▪ StringMatchQ ▪ StringFreeQ ▪ LetterQ ▪ DigitQ ▪ SyntaxQ ▪ ...

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