• Sean Eskapp (6/6) Jan 09 2011 I'm trying to use the array() function in std.array to convert a transfo...
• Guilherme Vieira (6/14) Jan 10 2011 It's easier to help if you provide sample code that produces the message...
• Daniel Murphy (9/18) Jan 10 2011 You're calling reduce on an empty range.

Sean Eskapp <eatingstaples gmail.com> writes:

I'm trying to use the array() function in std.array to convert a transformed
array using map (std.algorithm) back to a dynamic array, from a Map. I keep
getting a cryptic error "object.Exception C:\Program Files
(x86)\D\dmd2\windows\bin\..\..\src\phobos\std\
algorithm.d(426): Cannot reduce an empty range w/o an explicit seed value.".
Am I misunderstanding how this is supposed to work?

Guilherme Vieira <n2.nitrogen gmail.com> writes:

It's easier to help if you provide sample code that produces the message. I
got that message today and fixed it, I just don't what was the problem.

-- 
Atenciosamente / Sincerely,
Guilherme ("n2liquid") Vieira


On Mon, Jan 10, 2011 at 1:25 AM, Sean Eskapp <eatingstaples gmail.com>wrote:

 I'm trying to use the array() function in std.array to convert a
 transformed
 array using map (std.algorithm) back to a dynamic array, from a Map. I keep
 getting a cryptic error "object.Exception C:\Program Files
 (x86)\D\dmd2\windows\bin\..\..\src\phobos\std\
 algorithm.d(426): Cannot reduce an empty range w/o an explicit seed
 value.".
 Am I misunderstanding how this is supposed to work?

"Daniel Murphy" <yebblies nospamgmail.com> writes:

"Sean Eskapp" <eatingstaples gmail.com> wrote in message 
news:igdu78$18kt$1 digitalmars.com...
 I'm trying to use the array() function in std.array to convert a 
 transformed
 array using map (std.algorithm) back to a dynamic array, from a Map. I 
 keep
 getting a cryptic error "object.Exception C:\Program Files
 (x86)\D\dmd2\windows\bin\..\..\src\phobos\std\
 algorithm.d(426): Cannot reduce an empty range w/o an explicit seed 
 value.".
 Am I misunderstanding how this is supposed to work?

You're calling reduce on an empty range.

reduce!"a*b"([1, 2, 3]); // fine, translates to 1 * 2 * 3
reduce!"a*b"([7]); // also fine, translates to 7
reduce!"a*b"([]); // what should this be?

Luckily you can call reduce with an extra argument giving the seed value:

reduce!"a*b"(1, []); // Calculates product for both empty and non-empty 
ranges.