Re: foreach automoatic counter?

[cym13 via Digitalmars-d-learn]

On Monday, 21 September 2015 at 16:32:25 UTC, French Football 
wrote:
On Monday, 21 September 2015 at 15:54:06 UTC, Justin Whear 
wrote:

On Monday, 21 September 2015 at 15:58:12 UTC, cym13 wrote:


Thankyou! .enumerate lets me iterate over a container with a 
counter.

--Related tangential question... If I have a DList, how do I 
insert into the middle of it? I'm trying .insertAfter but it 
wants a range and apparently I can only slice an entire Dlist 
with [].

I had to look into phobos sources 
(/usr/include/dlang/dmd/std/containers/dlist.d) to find a 
unittest, and judging from it it seems inserting in the middle of 
a DList just wasn't taken seriously.

    @safe unittest
    {
        import std.algorithm : equal;

        auto dl = DList!string(["a", "b", "d"]);
        dl.insertAfter(dl[], "e"); // insert at the end
        assert(equal(dl[], ["a", "b", "d", "e"]));
        auto dlr = dl[];
        dlr.popBack(); dlr.popBack();
        dl.insertAfter(dlr, "c"); // insert after "b"
        assert(equal(dl[], ["a", "b", "c", "d", "e"]));
    }

There is however a nicer method using std.ranges:

    void main(string[] args) {
        import std.stdio;
        import std.range;
        import std.container: DList;

        auto list = DList!int([1, 2, 3, 5]);

        list.insertBefore(list[].drop(3), 4);

        foreach(n ; list)
            writeln(n);
    }

I hope this is helpful.