Find if keys are in two dimensional associative array

[BCS]

Hello Michal,

> if one has double indexed aa, how to find that it contains value under
> keys 'a' and 123
> 
> float[int][char] aa;
> 
> aa['a'][123] = 4.56;
> 
> I had to make following helper function. Is there more elegant way /
> built in into D?
> 
> float* isIn = doubleIn(123, 'a');
> 
> float* doubleIn (int i, char ch) {
> 
> float[int]* first = ch in aa;
> 
> if (first is null)
> return null;
> else
> return i in *first;
> }

That's how I'd do it, more or less. However I'd skip the function (or go 
with the more general case as shown by Simen).

float* isIn = null;
if(auto a = 'a' in aa) b = 123 in *a;