predicate

I'm working on an iphone application and I have a simple many-to-many relationship set up with Group and Contact objects. A group can have many contacts and contacts can belong to multiple groups. I'm trying to select all groups that a particular contact does NOT already belong to using the following predicate. (Note: the uid field is a string field that I used to uniquely identify contact entities) [NSPredicate predicateWithFormat:@"ALL contacts.uid != %@", contactUId] According to Apple's Predicate Programming Guide, the ALL aggregate operation is valid but I get the following exception

I am trying to learn lisp, using emacs dialect and I have a question. let us say list has some members, for which predicate evaluates to false. how do I create a new list without those members? something like { A in L: p(A) is true } . in python there is filter function, is there something equivalent in lisp? if not, how do I do it? Thanks rootzlevel These functions are in the CL package, you will need to (require 'cl) to use them: (remove-if-not #'evenp '(1 2 3 4 5)) This will return a new list with all even numbers from the argument. Also look up delete-if-not , which does the same, but

I often find myself in the need to filter a Stream or to use a predicate that checks if a given field has a given value. Say for example I have this POJO: public class A { private Integer field; public A(final Integer field) { this.field = field; } public Integer getField() { return field; } } And I want to filter a Stream of objects based on the value of the field : final Integer someValue = 42; Stream.of(new A(42), new A(1729), new A(42), new A(87539319), new A(null)) .filter(a -> Objects.equals(a.getField(), someValue)) ... Would there be a convenience method to generate the predicate for

Can you give some example or a link to a topic. Andrey Sidorov A predicate is a C++ function returning a boolean or an object having a bool operator() member. A unary predicate takes one argument, a binary takes two, and so on. Examples of questions predicates can answer for a particular algorithm are: Is this element what we are looking for? Is the first of two arguments ordered first in our order? Are the two arguments equal? Almost all STL algorithms take a predicate as last argument. You can construct new predicates using standard, self-defined, and/or predicate-making classes ( here is a

I'm working through the tutorial here (learning Swift) for my first app: http://www.appcoda.com/search-bar-tutorial-ios7/ I'm stuck on this part (Objective-C code): - (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope { NSPredicate *resultPredicate = [NSPredicate predicateWithFormat:@"name contains[c] %@", searchText]; searchResults = [recipes filteredArrayUsingPredicate:resultPredicate]; } Can anyone advise how to create an equivalent for NSPredicate in Swift? This is really just a syntax switch. OK, so we have this method call: [NSPredicate predicateWithFormat:@

can anyone help me out in solving my issue. I am using the code given below: public IEnumerable<InvoiceHeader> Getdata(Expression<Func<InvoiceHeader, bool>> predicate) { return AccountsContext.InvoiceHeaders.Include("Company").Include("Currency") .Include("BusinessPartnerRoleList").Include("DocumentType") .Where(predicate); } ..... In my code I am using as below Expression<Func<InvoiceHeader, bool>> predicate = PredicateBuilder.True<InvoiceHeader>(); predicate = predicate.And(o => o.CompanyId == oInvoiceHeader.CompanyId); List<InvoiceHeader> lstInvheader=Getdata(predicate).ToList(); By doing