[datatable-help] Report an unexpected behavior in data.table 1.5

[Matthew Dowle]

Great stuff thanks for the details. That gives me enough to go on. Will
try to look at the weekend ...
Matthew

> Sigh, I gave you some misleading information. I was saying that it
> doesn't work within function, and work in global. I was wrong. It
> doesn't work even in global in 1.5.
>
>> data.table(A=1:10,B=rnorm(10),key="A")[eval(parse(text="B>0"))]
> Error in `[.data.table`(data.table(A = 1:10, B = rnorm(10), key = "A"),  :
>   i has not evaluated to logical, integer or double
>
> What I was using eval(...) in global is j expression, i.e.
> [,eval(...)] rather than i expression [eval(...)]
> data.table(A=1:10,B=rnorm(10),key="A")[,eval(parse(text="B"))]
>
> Apologize for the bothersome information.
>
> Best regards,
>
> 2010/9/2 Branson Owen <branson.owen at gmail.com>:
>> Alright, my fault. I was reckless again. I forgot my standard R using
>> data.table 1.4, and thus the problem doesn't exist. Now, I can give
>> you the error example with standard R and appropriate data.table
>> version.
>>
>>> fn <- function(criteria)
>>> data.table(A=1:10,B=rnorm(10),key="A")[eval(parse(text=criteria))]
>>> fn("B>0")
>>
>> [data.table 1.5]
>>
>> Error in `[.data.table`(data.table(A = 1:10, B = norm(10), key = "A"),
>>  :
>>  i has not evaluated to logical, integer or double
>>
>> [data.table 1.4]
>>    A      B
>> [1,] 3   0.67
>> [2,] 4   1.16
>> [3,] 6   1.01
>> [4,] 8   0.09
>>
>> Again, the solution is to add {} around eval(...)
>>
>> ** Discussion of similar problems I have bumped into **
>> Is it an environment? namespace? or search.path? problem. (Sorry, at
>> this moment I only have rough impression about these concepts)
>> Anyway, I have bumped into this kind of problem three times including
>> this one. Just want to summarize. Might help identify where the
>> problem is.
>>
>> a. DT[J(unique(COL))]
>> This is the bug Matthew just fixed. [...] can't see function defined
>> outside. I was using {} wrapper to solve this problem.
>>
>> b. DT[...] can't see the local variable defined within a function in
>> data.table 1.4. This bug is really painful. I have to defined some
>> variables outside the function. Make it available in global
>> environment. This bug has been fixed in 1.5 before I can report it.
>>
>> c. the bug I reported in the beginning
>>
>> The first two bugs belongs to data.table 1.4, and were fixed in
>> current version 1.5. Bug (c) doesn't exist in 1.4. Thus, I suspect
>> that fixing the (a) and (b) bugs caused the new bug (c)?
>>
>> Please take your time to look at it if you are interested. This bug is
>> really a minor issue compared to bug (b), which I am glad has been
>> fixed.
>>
>> Best regards,
>>
>> 2010/9/2 Branson Owen <branson.owen at gmail.com>:
>>> Ha, I found the problem is caused by the special REvolution R 3.1.1
>>> when I tried to re-produce the error. The underlying R is 2.9.2 which
>>> is not allowed for data.table 1.5 (I rebuild the package to remove the
>>> version restriction). Sorry, I didn't check it on standard R first
>>> (Usually, I do.) An embarrassing mistake. :-P I know my working
>>> environment is dangerous, and I will upgrade to their new version 4.0
>>> soon, which is build on R-2.11.1. It was lucky that putting a {}
>>> wrapper can solve my problem.
>>>
>>> Best regards,
>>>
>>> 2010/8/31 Matthew Dowle <mdowle at mdowle.plus.com>:
>>>> I just have 30 seconds for quick reply ... can see I'll need
>>>> reproducible example for this one please; it will probably depend on
>>>> contents of 'criteria', columns of DT and arguments of the function
>>>> within which it fails. With that I can take a look later ... Thanks.
>>>> On Tue, 2010-08-31 at 08:40 -0500, Branson Owen wrote:
>>>>> Dear all,
>>>>> I just updated my data.table package from 1.4 to 1.5 yesterday. Ran
>>>>> into a small problem that has been solved. Just want to report it
>>>>> since I don't quite understand it.
>>>>> > DT[eval(parse(text = criteria))]
>>>>> This command is working in 1.4, but not everywhere in 1.5. It show
>>>>> this error message when called within a function.
>>>>> Error in `[.data.table`(Data, eval(parse(text = criteria))) :
>>>>>   i has not evaluated to logical, integer or double
>>>>> However, it works in global environment? My solution for a function
>>>>> call is, again, wrap it with {}. Therefore,
>>>>>
>>>>> > DT[ { eval(parse(text = criteria)) } ]
>>>>>
>>>>> solved my new problem.
>>>>>
>>>>> It didn't behave like this in 1.4. I guess this is because of the
>>>>> favor Matthew did for me for the DT[ { CJ } ] bug. If nothing can be
>>>>> perfect, I pretty much like the current setup. There wasn't many
>>>>> eval(), but there are lots of CJ/J in my codes.
>>>>>
>>>>> Just thought you will be interested. Thank you very much for your
>>>>> efforts and great work.
>>>>>
>>>>> Best regards,
>>>
>>
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