Formatted output not on screen but in a string

[Adam D. Ruppe]

On Friday, 21 May 2021 at 22:37:34 UTC, Alain De Vos wrote:
> Next code format a string and prints it.
> But I want the formatted string stored in a string
> ```
> //Decimal place separator %,
> writefln!"%,s"(123456789);
> //123,456,789
> ```

std.format.format