predicate

Consider the arrays below. The arrays contain objects of type 'Alpha'. We only care about the property username which is of type NSString . NSArray *some_usernames = @[ <multiple values of type Alpha> ] NSArray *all_usernames = @[ <multiple values of type Alpha> ] I basically want a list of all the usernames that are not in the array some_usernames , i.e. NSArray *remaining_usernames = @[ <all_usernames but not in some_usernames> ]; The way I would intend to do is: NSPredicates *predicates; for (Alpha *alpha in some_usernames) { predicate = [predicate with @"username != %@", alpha.username];

I have the following code: public boolean isImageSrcExists(String imageSrc) { int resultsNum = 0; List<WebElement> blogImagesList = driver.findElements(blogImageLocator); for (WebElement thisImage : blogImagesList) { if (thisImage.getAttribute("style").contains(imageSrc)) { resultsNum++; } } if (resultsNum == 2) { return true; } else { return false; } } What is the proper way of converting it to use Java 8 Stream s? When I'm trying to use map() , I get an error since getAttribute isn't a Function . int a = (int) blogImagesList.stream() .map(WebElement::getAttribute("style")) .filter(s -> s

I want to do something like this: List<SomeClass> list1 = ... List<SomeClass> list2 = ... Predicate<SomeClass> condition = ... ... list2.RemoveAll (!condition); ... list2.AddRange (list1.FindAll (condition)); However, this results in a compiler error, as ! can't be applied to Predicate<SomeClass> . Is there any way to do this? You could use a lambda expression to define an anonymous delegate inplace that is the result of negating the result of the predicate: list.RemoveAll(x => !condition(x)); Another option: static Predicate<T> Negate<T>(Predicate<T> predicate) { return x => !predicate(x); }

I have the following call in my code: var dbResults = new List<CrossReferenceRelationshipEF>(); dbResults = dateTimeFilter == null ? new List<CrossReferenceRelationshipEF>( CrossReferenceRelationshipRepository.GetAll() .ToList().OrderBy(crr => crr.ToPartner)) : new List<CrossReferenceRelationshipEF>( CrossReferenceRelationshipRepository.SearchFor( crr => crr.HistoricEntries .Any(he => he.ModifiedDatetime > dateTimeFilter)) .ToList().OrderBy(crr => crr.ToPartner)); and I am trying to use FakeItEasy to verify that when the dateTimeFilter has a value, the SearchFor(…) is being called within my

Have a curiosity related to Prolog predicate control. Supposedly I have a predicate f(A,X) and g(B). f(A,X):- a,b,c, g(X). g(B):- true. a - returns true b - returns true. c - returns false. where a,b and c are random predicates. How can I continue to evaluate g(X) in the predicate f(A,X) if c returns false? If your intention is to define f(A,X) such that g(X) should be evaluated whether or not c fails, then either: You could encode this using implication ( -> ) and/or disjunction ( ; ), or f(A,X) doesn't need to be defined in terms of c . This assumes c has no side-effects (e.g., asserting

Is there a javascript library that will allow me to express object predicates in a DSL similar to MongoDB's query language? For the sake of clarity in a large program, I'd like to be able to say: var obj = { a: 1, b: 'abcdefg' }, qry = { a: { $gt: 0 }, b: /^abc/ }; if(query(qry).matches(obj)) { // do something appropriate since } instead of: var obj = { a: 1, b: 'abcdefg' }; if(obj.a>0 && qry.b.test(obj.b)) { // do something appropriate } I'm using Node.js, so anything on NPM would be great. It would be an added bonus if the library can select objects out of an array as well as just matching

I am trying to build a complex xpath expression which will answer the following condition. From the XML data below, returns the User entity which: His loginname is " user1 " His name is " User 1 " He has 2 different profiles values which are " operator " and " admin " (I don't know the exact order ahead) <user> <login>user1</login> <name>User 1</name> <profile> <value>admin</value> <id>2</id> <description>admin users</description> </profile> <profile> <value>operator</value> <id>1</id> <description>Operator</description> </profile> </user> <user> <login>user2</login> <name>User 2</name>