[R] Value Lookup from File without Slurping

[Gundala Viswanath]

Hi,

> Unless you specify an in-memory database the database is stored on disk.

Thanks for your explanation.
I just downloaded 'sqldf'.

Where can I find the option for that? In sqldf I can't see the command.

I looked at:
envir = parent.frame()

doesn't appear to be the one.

- Gundala Viswanath
Jakarta - Indonesia

>
> On Fri, Jan 16, 2009 at 10:59 AM, Gundala Viswanath <gundalav at gmail.com> wrote:
>> Hi Gabor,
>>
>>> the file itself is read  into a database
>>
>> The above doesn't use RAM memory?
>>
>> Rgds,
>> GV.
>>
>>> without ever going through R so your memory requirements correspond to what
>>> you extract, not the size of the file.
>>>
>>> On Fri, Jan 16, 2009 at 10:49 AM, Gundala Viswanath <gundalav at gmail.com> wrote:
>>>> Hi Gabor,
>>>>
>>>> Do you mean storing data in "sqldf', doesn't take memory?
>>>> For example, I have 3GB data file. with standard R object using read.table()
>>>> the object size will explode twice ~6GB. My current 4GB RAM
>>>> cannot handle that.
>>>>
>>>> Do you mean with "sqldf", this is not the issue?
>>>> Why is that?
>>>>
>>>> Sorry for my naive question.
>>>>
>>>> - Gundala Viswanath
>>>> Jakarta - Indonesia
>>>>
>>>>
>>>>
>>>> On Fri, Jan 16, 2009 at 9:09 PM, Gabor Grothendieck
>>>> <ggrothendieck at gmail.com> wrote:
>>>>> On Fri, Jan 16, 2009 at 5:52 AM, r at quantide.com <r at quantide.com> wrote:
>>>>>> I agree on the database solution.
>>>>>> Database are the rigth tool to solve this kind of problem.
>>>>>> Only consider the start up cost of setting up the database. This could be a
>>>>>> very time consuming task if someone is not familiar with database
>>>>>> technology.
>>>>>
>>>>> Using sqldf as mentioned previously on this thread allows one to use
>>>>> the SQLite database with no setup at all.  sqldf automatically creates
>>>>> the database, generates the record layout, loads the file (not going through
>>>>> R but outside of R so R does not slow it down) and extracts the
>>>>> portion you want into R issuing the appropriate calls to RSQLite/DBI and
>>>>> destroying the database afterwards all automatically.  When you
>>>>> install sqldf it automatically installs RSQLite and the SQLite database
>>>>> itself so the entire installation is just one line: install.packages("sqldf")
>>>>>
>>>>> ______________________________________________
>>>>> R-help at r-project.org mailing list
>>>>> 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.
>>>>>
>>>>
>>>
>>
>