This boils down to whether or not a lambda’s type differs across translation units. If it does, it may affect template argument deduction and potentially cause different functions to be called – in what are meant to be consistent definitions. That would violate the ODR (see below). However, that isn’t intended. In fact, this problem … Read more
You say you want to sort by value, but you don’t have that in your code. Pass a lambda (or method reference) to sorted to tell it how you want to sort. And you want to get the keys; use map to transform entries to keys. List<Type> types = countByType.entrySet().stream() .sorted(Comparator.comparing(Map.Entry::getValue)) .map(Map.Entry::getKey) .collect(Collectors.toList());
I assume you are running this under Java 9? You are not altering the SIZED property of the stream, so there is no need to execute either map or peek at all. In other words all you care is about count as the final result, but in the meanwhile you do not alter the initial … Read more
First define the lambda object, then pass it to the template’s type using decltype and also pass it directly to the constructor. auto comp = []( adjist a, adjlist b ) { return a.second > b.second; }; priority_queue< adjlist_edge , vector<adjlist_edge>, decltype( comp ) > adjlist_pq( comp );
The RTM version of Entity Framework 4.1 actually includes extension methods in the EntityFramework.dll file, for eager loading with lambda through the Include function. Just include the DLL in your project and you should be able to write code like: var princesses1 = context.Princesses.Include(p => p.Unicorns).ToList(); Remember to add an Import/Using statement to include the … Read more
you can transpose it and header row becomes a column. then: =TRANSPOSE(QUERY(TRANSPOSE(A1:C), “where Col1 matches ‘bb header|student'”, )) where A1:C is your named range (including header row) update: =QUERY({AI1:AK6}, “select Col2,Col3 where Col1=’Jones'”, 1) dynamically: =LAMBDA(p, t, s, QUERY({AI1:AK6}, “select Col”&t&”,Col”&s&” where Col”&p&”=’Jones’ order by Col”&t&” desc”, 1)) (MATCH(“principal”, AI1:AK1, ), MATCH(“teacher”, AI1:AK1, ), MATCH(“student”, … Read more
FINAL UPDATE: The bug has been fixed in C# 5. Apologies again for the inconvenience, and thanks for the report. Original analysis: I can reproduce the problem with the command-line compiler. It certainly looks like a bug. It’s probably my fault; sorry about that. (I wrote all of the lambda-to-delegate conversion checking code.) I’m in … Read more
It’s pretty well-known that general function equality is undecidable in general, so you’ll have to pick a subset of the problem that you’re interested in. You might consider some of these partial solutions: Presburger arithmetic is a decidable fragment of first-order logic + arithmetic. The universe package offers function equality tests for total functions with … Read more
I believe VS2010 to be right this time, and I’d check if I had the standard handy, but currently I don’t. Now, it’s exactly like the error message says: You can’t capture stuff outside of the enclosing scope of the lambda.† grid is not in the enclosing scope, but this is (every access to grid … Read more
The Expression API supports this in .NET 4.0, but sadly the C# compiler doesn’t add any extra candy to support. But the good news is that you can trivially take a “get” expression (which the C# compiler can write) and re-write it as a “set” expression. And even better; if you don’t have .NET 4.0, … Read more