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Documentation / Mathematica / Built-in Functions / Programming / Pattern Matching /

PatternTest

FilledSmallSquare p?test is a pattern object that stands for any expression which matches p, and on which the application of test gives True.

FilledSmallSquare Any result for test[pval] other than True is taken to signify failure.

FilledSmallSquare Example: _?NumberQ represents a number of any type. The _ matches any expression, and ?NumberQ restricts to any expression which gives True on application of the number test NumberQ.

FilledSmallSquare The operator ? has a high precedence. Thus _^_?t is _^(_?t) not (_^_)?t.

FilledSmallSquare In a form such as __?test every element in the sequence matched by __ must yield True when test is applied.

FilledSmallSquare See Section 2.3.5.

FilledSmallSquare See also: Condition, Element.

FilledSmallSquare New in Version 1.

Further Examples