All .net developers know that LINQ can be used to conveniently extract and process data from arrays, enumerable classes, XML documents, relational databases, and third-party data sources. These concepts are adopted by other programming languages such as Java, Javascript, Ruby etc.
var cityWiseSalary = from comp in ListCompany select new { comp.Name, Emp = (from emp in comp.ListEmp group emp by emp.Address.City into CityWiseEmp select new { State = CityWiseEmp.Key, TotalSalary = CityWiseEmp.Sum(emp => emp.salary) }) };
There is no reason that we can’t port it to Objective-C. By using LinqToObjectiveC, we could write Objective-C code like:
NSArray* input = @[@"Frank", @"Jim", @"Bob"];
NSDictionary* dictionary = [input linq_toDictionaryWithKeySelector:^id(id item) {
return [item substringToIndex:1];
} valueSelector:^id(id item) {
return [item lowercaseString];
}];
// result:
// (
// F = frank;
// J = jim;
// B = bob;
// )
Comparing to the old school KVC way:
NSArray *payees = [arrayOfTransactionsArrays valueForKeyPath:@"@distinctUnionOfArrays.payee"];
The API is not so intuitive, and not composable, is it?
