Regarding std.array.Appender

[Suliman via Digitalmars-d-learn]

On Tuesday, 13 October 2015 at 13:55:07 UTC, anonymous wrote:
> On Tuesday 13 October 2015 15:47, Suliman wrote:
>
>> something like: auto content = file.byLine.map!("start " ~ 
>> a=>a ~ " end");
>
> That's not how it works at all. Maybe stick to the examples of 
> whatever resource you're learning from, for now.

Yes, I understand that it's not work exactly like I try to use 
it, but which function can solve my problem?