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numberp (PREDICATE)

Format: (numberp <exp>)

Required arguments: 1

<exp>: any LISP expression

The predicate numberp returns T if <exp> evaluates to a number (i.e. an object of type integer, ratio, float, or complex); numberp returns NIL otherwise.

Examples:

>(numberp 1/2)
T

>(numberp 1235439)
T

>(numberp (/ 5 1.23))
T

>(numberp #C(1.2 -0.9))
T

>(numberp '(+ 1 2 3))
NIL