On 02/09/2013 10:14 PM, Simon wrote:
> Hi, I'm new to the D programming language. Overall I'm liking
> things very much, but I'm still getting the hang of a few things.
>
> Here's a basic programming pattern: I have a class called Thing,
> and while I'm coding I decide I need N Thing instances.
>
> In C++ that's a matter of
>
> std::vector<Thing> things(N);
>
> In python, I can use a list comprehension.
>
> things = [Thing() for _ in range(N)]
>
> However, the obvious D version doesn't work.
>
> auto things = new Thing[N];
>
> Because Thing.init is null, this produces an array of null
> references. Of course, I can write a for loop to fill in the
> array after creation, but this feels very un-D-like. Is there a
> straightforward way to create a bunch of class instances?
Here is one way:
import std.stdio;
import std.range;
import std.algorithm;
class Thing
{
int i;
this(int i)
{
this.i = i;
}
}
void main()
{
auto things = iota(10).map!(i => new Thing(i))().array;
}
Ali
--
D Programming Language Tutorial: http://ddili.org/ders/d.en/index.html
