[datatable-help] `with=F` in the `i` Argument

[Michael Smith]

Devs,

Is this a bug? It works in 1.9.2 but not in the 1.9.3 development version:

DT <- data.table(a = 1:4, b = 8:5)
for (i in c("a", "b"))
  print(DT[order(DT[, i, with = FALSE])])

Error in forder(DT, DT[, i, with = FALSE]) :
  Column '1' is type 'list' which is not supported for ordering currently.


Thanks,

M


On 05/31/2014 12:44 PM, G See wrote:
> Hi Michael,
> 
> I would use get()
> 
> DT <- data.table(a = 1:4, b = 8:5)
> for (i in c("a", "b"))
>   print(DT[order(get(i))])
> 
> For what it's worth, your solution doesn't seem to work in data.table
> 1.9.3 (svn rev. 1278):
> 
>> for (i in c("a", "b"))
> +   print(DT[order(DT[, i, with = FALSE])])
> Error in forder(DT, DT[, i, with = FALSE]) :
>   Column '1' is type 'list' which is not supported for ordering currently.
> 
> 
> HTH,
> Garrett
> 
> On Fri, May 30, 2014 at 11:01 PM, Michael Smith <my.r.help at gmail.com> wrote:
>> All,
>>
>> I'm trying to order the rows according to several columns at a time:
>>
>> DT <- data.table(a = 1:4, b = 8:5)
>> for (i in c("a", "b"))
>>   print(DT[order(i), with = FALSE])
>>
>> It doesn't work, since `with` seems to be about the `j` argument, but
>> not the `i` argument, according to `?data.table`.
>>
>> I found the following workaround, but wonder whether there is a more
>> elegant way to do it:
>>
>> for (i in c("a", "b"))
>>   print(DT[order(DT[, i, with = FALSE])])
>>
>> Thanks,
>> M
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