For this use case of optionally present data, Nullable would seem appropriate (although this is 0.4-only).
http://julia.readthedocs.org/en/latest/manual/types/#nullable-types-representing-missing-values Thanks, Jiahao Chen Research Scientist MIT CSAIL On Sat, May 30, 2015 at 2:08 PM, Tobias Knopp <tobias.kn...@googlemail.com> wrote: > There is one exception though, which is keyword arguments > > > Am Samstag, 30. Mai 2015 03:49:45 UTC+2 schrieb Steven G. Johnson: >> >> *No!* This is one of the most common misconceptions about Julia >> programming. >> >> The type declarations in function arguments have *no impact* on >> performance. Zero. Nada. Zip. You *don't have to declare a type at >> all* in the function argument, and it *still* won't matter for >> performance. >> >> The argument types are just a filter for when the function is applicable. >> >> The first time a function is called, a specialized version is compiled >> for the types of the arguments that you pass it. Subsequently, when you >> call it with arguments of the same type, the specialized version is called. >> >> Note also that a default argument foo(x, y=false) is exactly equivalent >> to defining >> >> foo(x,y) = ... >> foo(x) = foo(x, false) >> >> So, if you call foo(x, [1,2,3]), it calls a version of foo(x,y) >> specialized for an Array{Int} in the second argument. The existence of a >> version of foo specialized for a boolean y is irrelevant. >> >
