length of string result not as expected

[jicman]

On Wednesday, 14 August 2013 at 03:00:00 UTC, Jonathan M Davis 
wrote:
> On Wednesday, August 14, 2013 04:53:34 jicman wrote:
>> Greetings.
>> 
>> import std.stdio;
>> 
>> void main()
>> {
>> char[] str = "不良反應事件和產品客訴報告"; // 13 chinese characters...
>> writefln(str.length);
>> }
>> 
>> this program returns 39. I expected to return 13. How do I know
>> the exact length of the characters that I have in a char[]
>> variable? Thanks.
>
> length gives you the length of the array, which is 39, because 
> it contains 39
> chars. If you want to know the number of code points in the 
> string as opposed
> to the number of code units (char is a UTF-8 code unit), then 
> use
> std.range.walkLength. e.g.
>
> writeln(walkLength(str));
>
> It'll iterate through the string and count up the number of 
> code points.
>
> - Jonathan M Davis

thanks, Jonathan.  That looks like D2, since D1 does not have 
std.range in its phobos library.