Predicates on Numbers

These are predicate functions that test a condition of a single number argument and returns t if the condition tests true and returns nil otherwise.

zerop x

Function

Tests for the condition that the given number x is zero.

plusp x

Function

Tests for the condition that the given number x is non-zero and positive.

minusp x

Function

Tests for the condition that the given number x is non-zero and negative.

oddp x

Function

Tests for the condition that the given number x is odd.

evenp x

Function

Tests for the condition that the given number x is even.