While Predicate has been introduced at the same time that List<T> and Array<T>, in .net 2.0, the different Func and Action variants come from .net 3.5. So those Func predicates are used mainly for consistency in the LINQ operators. As of .net 3.5, about using Func<T> and Action<T> the guideline states: Do use the new … Read more
To find the first element in a sequence seq that matches a predicate: next(x for x in seq if predicate(x)) Or simply: Python 2: next(itertools.ifilter(predicate, seq)) Python 3: next(filter(predicate, seq)) These will raise a StopIteration exception if the predicate does not match for any element. To return None if there is no such element: next((x … Read more
A predicate is a function that returns true or false. A predicate delegate is a reference to a predicate. So basically a predicate delegate is a reference to a function that returns true or false. Predicates are very useful for filtering a list of values – here is an example. using System; using System.Collections.Generic; class … Read more
Predicate.not( … ) java-11 offers a new method Predicate#not So you can negate the method reference: Stream<String> s = …; long nonEmptyStrings = s.filter(Predicate.not(String::isEmpty)).count();