COP 3223H meeting -*- Outline -*-

* Predicate functions

** definition
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             PREDICATES

def: a *predicate* is a function that


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        ... returns a Boolean value

        Predicates are useful for abstracting conditions

** examples
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             EXAMPLE PREDICATES

def odd(n):
    """Return True just when n is an odd number."""



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        ... return n % 2 == 1

        Q: How would you define the predicate "even"?

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           FOR YOU TO DO

Write a predicate, positive(n), that returns True
just when n is a positive number.





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        ... def positive(n):
                """Is n greater than zero?"""
                return n > 0
                
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          FOR YOU TO DO

Write a predicate, strictly_ascending(n1, n2, n3)
that returns True just when n1 < n2 and n2 < n3.





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      ... def strictly_ascending(n1, n2, n3)
              """Return True just when n1 < n2 and n2 < n3"""
              return n1 < n2 and n2 < n3