[R] fread transforms numbers

[Santosh]

Dear Rxperts..
I am using R version 3.2.3 on Linux.. it says bit64 is not available for R
version 3.2.3..

Thanks and your assistance much appreciated!
Best regards,
Santosh


On Wed, Mar 22, 2017 at 7:50 PM, Santosh <santosh2005 at gmail.com> wrote:

> Thanks so much for your suggestions! Will try them out!
>
> Santosh
>
> On Wed, Mar 22, 2017 at 12:17 PM, Matt Dowle <mattjdowle at gmail.com> wrote:
>
>> Thanks Bill for cc.
>>
>> Santosh,
>>
>> I'm almost certain you don't have package bit64 installed.  When you do
>> it works fine :
>>
>> > remove.packages("bit64")
>> > data.table::fread("9876543210\n")
>>               V1
>> 1: 4.879661e-314
>> > install.packages("bit64")
>> > data.table::fread("9876543210\n")
>>            V1
>> 1: 9876543210
>>
>> News for data.table v1.10.2 on CRAN 31 Jan 2017 contained :
>>
>> * When fread() or print() see integer64 columns are present, bit64's
>> namespace is now automatically loaded for convenience.
>>
>> However, when data.table loads the namespace there is a bug in this
>> function :
>>
>> > data.table:::require_bit64
>> function ()
>> {
>>     tt = try(requireNamespace("bit64", quietly = TRUE))
>>     if (inherits(tt, "try-error"))
>>         warning("Some columns are type 'integer64' but package bit64 is
>> not installed. Those columns will print as strange looking floating point
>> data. There is no need to reload the data. Simply install.packages('bit64')
>> to obtain the integer64 print method and print the data again.")
>> }
>>
>> The intent was to display that nice helpful message to you.   Due to this
>> report, I can see now that I shouldn't have wrapped requireNamespace() with
>> try() because  requireNamespace() returns TRUE or FALSE anyway. Even though
>> requireNamespace() prints 'Failed with error' it doesn't actually throw an
>> error.  I'll change data.table's function to the following :
>>
>> if (!requireNamespace("bit64", quietly = TRUE))
>>     warning("Some columns ...")
>>
>> bit64 is correctly Suggests not Depends.   It's just unfortunate the
>> intended message wasn't displayed.
>>
>> Santosh, in future please follow the data.table support guide here:
>> https://github.com/Rdatatable/data.table/wiki/Support.  r-help is not
>> supposed to be used for package support.  The main thing though is thanks
>> for helping me find this bug.
>>
>> Thanks,
>> Matt
>>
>>
>> On Wed, Mar 22, 2017 at 10:22 AM, William Dunlap <wdunlap at tibco.com>
>> wrote:
>>
>>> Here is a way to reproduce the problem:
>>>   > data.table::fread("9876543210\n") # number bigger than 2^31-1
>>>                 V1
>>>   1: 4.879661e-314
>>> and your work-around does fix things up
>>>   > data.table::fread("9876543210\n", colClasses="numeric")
>>>              V1
>>>   1: 9876543210
>>>
>>> Bill Dunlap
>>> TIBCO Software
>>> wdunlap tibco.com
>>>
>>>
>>> On Wed, Mar 22, 2017 at 9:58 AM, Jeff Newmiller
>>> <jdnewmil at dcn.davis.ca.us> wrote:
>>> > You failed to provide a reproducible example, and you posted HTML so
>>> the quality of any answer will be limited by the quality of your question.
>>> >
>>> > My stab at your problem is that you should read ?fread, and in
>>> particular should try using the colClasses argument.
>>> > --
>>> > Sent from my phone. Please excuse my brevity.
>>> >
>>> > On March 22, 2017 8:52:55 AM PDT, Santosh <santosh2005 at gmail.com>
>>> wrote:
>>> >>Hi
>>> >>
>>> >>I have been using "fread" utility of "data.table" packge .. on a
>>> >>dataset of
>>> >>about 20 million rows. It's a fantastic package to read datasets. Thank
>>> >>you, Matt D.
>>> >>
>>> >>However, I am faced with a peculiar instance of  certain numbers in a
>>> >>column being transformed.
>>> >>
>>> >>In the dataset, a column has values ranging from 1 to 9##########
>>> >>(nchar(x)=11, e.g. 98765432109). After using "fread" to read the
>>> >>dataset,
>>> >>values in all the columns are displayed correctly upto the first 1000
>>> >>rows.
>>> >>If "fread" is applied for reading >1000 rows of  the total of 20Million
>>> >>rows, the values in only this (column (having wide range of values) are
>>> >>displayed as x.xxxxxxxe-3yy. (e.g. 3.5639877e-324)
>>> >>
>>> >>I tried reading all the columns as "character" and didn't help.
>>> >>
>>> >>Would highly appreciate your assistance!
>>> >>
>>> >>Thanks so much in advance.
>>> >>
>>> >>Best regards,
>>> >>Santosh
>>> >>
>>> >>       [[alternative HTML version deleted]]
>>> >>
>>> >>______________________________________________
>>> >>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> >>https://stat.ethz.ch/mailman/listinfo/r-help
>>> >>PLEASE do read the posting guide
>>> >>http://www.R-project.org/posting-guide.html
>>> >>and provide commented, minimal, self-contained, reproducible code.
>>> >
>>> > ______________________________________________
>>> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> > https://stat.ethz.ch/mailman/listinfo/r-help
>>> > PLEASE do read the posting guide http://www.R-project.org/posti
>>> ng-guide.html
>>> > and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>>
>

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