What does ! Stand for in map! and filter! function calls?

[Cym13]

On Sunday, 2 June 2019 at 15:48:54 UTC, Rnd wrote:
> I have recently started using Dlang, hence this basic question. 
> Thanks for your insight.

To know more about D you should take the time to do the D tour 
[1] which provides you with general knowledge of most of D's 
functionalities and vocabulary.

To know more about templates specifically, check out this 
tutorial [2].

[1]: https://tour.dlang.org/
[2]: http://nomad.uk.net/articles/templates-in-d-explained.html