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
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: essentially Func<T, bool>; asks the question “does the specified argument satisfy the condition represented by the delegate?” Used in things like List.FindAll. Action: Perform an action given the arguments. Very general purpose. Not used much in LINQ as it implies side-effects, basically. Func: Used extensively in LINQ, usually to transform the argument, e.g. by … Read more
You need to call ignoring with exception to ignore while the WebDriver will wait. FluentWait<WebDriver> fluentWait = new FluentWait<>(driver) .withTimeout(30, TimeUnit.SECONDS) .pollingEvery(200, TimeUnit.MILLISECONDS) .ignoring(NoSuchElementException.class); See the documentation of FluentWait for more info. But beware that this condition is already implemented in ExpectedConditions so you should use WebElement element = (new WebDriverWait(driver, 10)) .until(ExpectedConditions.elementToBeClickable(By.id(“someid”))); *Update for … 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();
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
Would the dynamic linq library help here? In particular, I’m thinking as a Where clause. If necessary, put it inside a list/array just to call .Where(string) on it! i.e. var people = new List<Person> { person }; int match = people.Where(filter).Any(); If not, writing a parser (using Expression under the hood) isn’t hugely taxing – … Read more