When using `chunkBy` (unary pred) the result is a list of tuples.  Each
tuple holds a key and a `Group` which belong to that key.
Where can I find the docs for this `Group` type (I have already tried
searching library on dlang.org)?

Thanks,
-- 
Bahman

On Tuesday, 12 July 2016 at 04:25:26 UTC, Bahman Movaqar wrote:
> When using `chunkBy` (unary pred) the result is a list of tuples.  Each
> tuple holds a key and a `Group` which belong to that key.
> Where can I find the docs for this `Group` type (I have already tried
> searching library on dlang.org)?
>
> Thanks,

The 'Group' type is an implementation detail -- a type used internally -- that you aren't supposed to care about. All you need to care about is that it's a range. The documentation for chunkBy [1] explains what the return type is.

[1] https://dlang.org/phobos/std_algorithm_iteration.html#.chunkBy

On 07/12/2016 11:06 AM, Mike Parker wrote:
> The 'Group' type is an implementation detail -- a type used internally -- that you aren't supposed to care about. All you need to care about is that it's a range. The documentation for chunkBy [1] explains what the return type is.
> 
> [1] https://dlang.org/phobos/std_algorithm_iteration.html#.chunkBy

Thanks.  Now since I can't do `takeOne` on `Group`[1], exactly what kind of range is `Group`?

[1] Error: no property 'takeOne' for type 'Group'

-- 
Bahman

On Tuesday, 12 July 2016 at 08:03:53 UTC, Bahman Movaqar wrote:
> On 07/12/2016 11:06 AM, Mike Parker wrote:
>> The 'Group' type is an implementation detail -- a type used internally -- that you aren't supposed to care about. All you need to care about is that it's a range. The documentation for chunkBy [1] explains what the return type is.
>> 
>> [1] https://dlang.org/phobos/std_algorithm_iteration.html#.chunkBy
>
> Thanks.  Now since I can't do `takeOne` on `Group`[1], exactly what kind of range is `Group`?
>
> [1] Error: no property 'takeOne' for type 'Group'

When you downloaded DMD, you also received the source to Phobos, so you can see for yourself. The only Group type I see the chunkBy implementations is at [1] (the link to the github viewer probably won't point to the same place for long, but you should be looking in the the version of ChunkByImpl for forward ranges). It's a forward range.

Do you have some sample code that shows the error?

[1] https://github.com/dlang/phobos/blob/master/std/algorithm/iteration.d#L1608

On 07/12/2016 01:01 PM, Mike Parker wrote:
> Do you have some sample code that shows the error?

Yes.  I'm working on Stockman[1] a playground to learn D.
In file `etl.d`, line 110 [2], if I change the line to
    auto refInvoice = group[1].takeOne();
the file will not compile.  I have attached the compile error to this
message.

Thanks,
-- 
Bahman


[1] https://github.com/bahmanm/stockman-d
[2] https://github.com/bahmanm/stockman-d/blob/master/source/etl.d#L110

On Tuesday, 12 July 2016 at 11:40:48 UTC, Bahman Movaqar wrote:
> On 07/12/2016 01:01 PM, Mike Parker wrote:
>> Do you have some sample code that shows the error?
>
> Yes.  I'm working on Stockman[1] a playground to learn D.
> In file `etl.d`, line 110 [2], if I change the line to
>     auto refInvoice = group[1].takeOne();
> the file will not compile.  I have attached the compile error to this
> message.
>
> Thanks,

What does group.writeln; output? That should give you a good sense of what is going on.

On 07/12/2016 01:40 PM, Bahman Movaqar wrote:
> Yes.  I'm working on Stockman[1] a playground to learn D.
> In file `etl.d`, line 110 [2], if I change the line to
>      auto refInvoice = group[1].takeOne();
> the file will not compile.  I have attached the compile error to this
> message.

Do you also add the import of takeOne? takeOne is not a range primitive, but a function that works on ranges. Need to import it in order to use it.

On 07/12/2016 04:23 PM, ag0aep6g wrote:
> On 07/12/2016 01:40 PM, Bahman Movaqar wrote:
>> Yes.  I'm working on Stockman[1] a playground to learn D.
>> In file `etl.d`, line 110 [2], if I change the line to
>>      auto refInvoice = group[1].takeOne();
>> the file will not compile.  I have attached the compile error to this
>> message.
> 
> Do you also add the import of takeOne? takeOne is not a range primitive, but a function that works on ranges. Need to import it in order to use it.

Stupid me!  Thanks :-)

-- 
Bahman

On 07/12/2016 04:21 PM, Edwin van Leeuwen wrote:
> On Tuesday, 12 July 2016 at 11:40:48 UTC, Bahman Movaqar wrote:
>> On 07/12/2016 01:01 PM, Mike Parker wrote:
>>> Do you have some sample code that shows the error?
>>
>> Yes.  I'm working on Stockman[1] a playground to learn D.
>> In file `etl.d`, line 110 [2], if I change the line to
>>     auto refInvoice = group[1].takeOne();
>> the file will not compile.  I have attached the compile error to this
>> message.
>>
>> Thanks,
> 
> What does group.writeln; output? That should give you a good sense of what is going on.

That's a good trick to know.  Thanks.

-- 
Bahman