filtering a row of a jagged array

[Simen Kjærås]

On Sunday, 11 August 2019 at 16:11:15 UTC, DanielG wrote:
> int[][] whatever = [
>     [0],
>     [0, 1, 2],
>     [5, 6, 7, 8, 9, 10]
> ];
> writeln(whatever[2]);                    // [5, 6, 7, 8, 9, 10]
> writeln(typeid(whatever[2]));            // int[]
> auto x = whatever[2].filter(x => x > 7); // error
>
> Error: template std.algorithm.iteration.filter cannot deduce 
> function from argument types !()(int[], void), candidates are: 
> ...
>
> Online example:
> https://run.dlang.io/is/LUXFuF
>
> ...
>
> I'm guessing I need to give the compiler some help 
> understanding that this is an array of ints, but 1) how, and 2) 
> why? [if typeid() seems to understand just fine?]

You're missing an exclamation mark after filter - it takes the 
predicate as a template argument. This compiles just fine:

     auto x = whatever[2].filter!(x => x > 7);

--
   Simen