Re: [R] write.csv +RMySQL request

From: Tristan Casey <nub_vulcanis_at_hotmail.com>
Date: Sat, 01 Mar 2008 14:59:24 +1000

Hello Haris,  

Thanks for that advice, yes that does work for me also, now the only problem is reading the csv.  

This is the format that write.csv is stored in as a variable;
> x[1] "\"\",\"x1\",\"x2\",\"x3\",\"x4\"" "\"1\",1,4,5,7" "\"2\",2,3,6,7"
R seems to insert alot of unnecessary \ and " into the variable. Consequently, I cannot get read.csv to process the file!  

I noticed that cat(x) prints a result that is perfect;  

> cat(x,sep=",")"","x1","x2","x3","x4","1",1,4,5,7,"2",2,3,6,7>
 

However once again, when I try to capture this output using textConnection, the resulting variable is transformed to the one above.  

Kind Regards,
Tristan Casey BPsySci (UQ)+ 4 Festa Court, Capalaba, QLD 4157H 8/33 Lilly St, Greenslopes, QLD 41200450 033 948

> CC: r-help_at_r-project.org> From: cskiadas_at_gmail.com> Subject: Re: [R] write.csv +RMySQL request> Date: Fri, 29 Feb 2008 10:50:34 -0500> To: nub_vulcanis_at_hotmail.com> > The following worked for me (put together after reading ? > textConnection). Put simply, all read/write command work with > "connections", which are if you like "devices that know how to read > or write things". textConnection creates such a device that writes > (or reads if we used open="r") to/from an already existing vector.> If the file argument to write.csv is not a connection, then it is > interpreted as a file name, and a connection to read/write on that > file is automatically made for you. The description in ?write.csv > explains this part.> > x <- character()> y<-textConnection("x", open="w")> write.csv(iris,file=y)> close(y)> > Haris Skiadas> Department of Mathematics and Computer Science> Hanover College> > On Feb 29, 2008, at 4:37 AM, Tristan Casey wrote:> > > Well that is certainly good news if !

 write.csv output can be stored > > directly to a character vector!> >> > I have tried to specify a vector within the file="" argument for > > example;> >> > write.csv(a,file="b") where b is a preexisting character vector> >> > This does not work. Do I need to define b as something else, like a > > textConnection?> >> >> >> Date: Fri, 29 Feb 2008 09:16:11 +0000> >> From: ripley_at_stats.ox.ac.uk> >> To: nub_vulcanis_at_hotmail.com> >> CC: jholtman_at_gmail.com; r-help_at_r-project.org> >> Subject: RE: [R] write.csv +RMySQL request> >>> >> On Fri, 29 Feb 2008, Tristan Casey wrote:> >>> >>> Ahh, my apologies I must admit that I don't fully understand> >>> textConnections fully. I have been reading up on th RODBC package > >>> as an> >>> alternative to RMySQL.> >>>> >>> With the file argument in write.csv, are you saying it is > >>> possible to> >>> write the csv formated data directly to a cell in a MySQL > >>> database? I am> >>> unsure what the variable 'con' must consist of.> >>> >> No!
 , that it is possible to write it to an R character vector.> >>> >>> W
ould this need to be a character string that initially connects > >>> to the> >>> database (dbConnect) then pastes the MySQL query? I am unsure how to> >>> specify where the data is going with the file/connection argument.> >>>> >>> Thanks> >>>> >>>> >>>> Date: Fri, 29 Feb 2008 08:44:58 +0000> >>>> From: ripley_at_stats.ox.ac.uk> >>>> To: nub_vulcanis_at_hotmail.com> >>>> CC: jholtman_at_gmail.com; r-help_at_r-project.org> >>>> Subject: RE: [R] write.csv +RMySQL request> >>>>> >>>> On Fri, 29 Feb 2008, Tristan Casey wrote:> >>>>> >>>>> Thanks again for your help.> >>>>>> >>>>> I am wanting my variable to store a character string exactly as > >>>>> the write.csv function would store as a csv text file;> >>>>>> >>>>> IE: My goal is to store a data frame of this construction;> >>>>>> >>>>> x1 x2> >>>>> 1 2> >>>>> 3 4> >>>>>> >>>>> as "X1","X2",1,2,3,4 (the same format as CSV).> >>>>>> >>>>> I am aware of the file argument, however that is the problem, > >>>>> storing to> >>>>> a physical t!
 ext file and then importing into the SQL database > >>>>> is a very> >>>>> inefficient way of doing things, especially when I can use > >>>>> RMySQL to> >>>>> send commands directly to the database.> >>>>> >>>> You seem however unaware of text connections. Neither of us > >>>> said anything> >>>> about using a 'physical text file', and the documentation for> >>>> write.csv says> >>>>> >>>> file: either a character string naming a file or a > >>>> connection open> >>>> for writing. '""' indicates output to the console.> >>>>> >>>> A 'text connection; is not a file (physical or otherwise).> >>>>> >>>>> >>>>>> >>>>> Kind Regards,> >>>>>> >>>>> Tristan Casey BPsySci (UQ)> >>>>> + 4 Festa Court, Capalaba, QLD 4157> >>>>> H 8/33 Lilly St, Greenslopes, QLD 4120> >>>>> 0450 033 948> >>>>>> >>>>>> >>>>>> >>>>>> Date: Fri, 29 Feb 2008 05:12:04 +0000> >>>>>> From: ripley_at_stats.ox.ac.uk> >>>>>> To: jholtman_at_gmail.com> >>>>>> CC: nub_vulcanis_at_hotmail.com; r-help_at_r-project.org> >>>>>> Su!  bject: Re: [R] write.csv +RMySQL request> >>>>>>> >>>>>> On Thu, 28 Fe
b 2008, jim holtman wrote:> >>>>>>> >>>>>>> ?capture.output> >>>>>>>> >>>>>>> myoutput <- capture.output(write.csv(...))> >>>>>>> >>>>>> It would be better to write directly to a text connection: see > >>>>>> the 'file'> >>>>>> argument to write.csv.> >>>>>>> >>>>>>> On Thu, Feb 28, 2008 at 7:34 PM, Tristan Casey > >>>>>>> <nub_vulcanis_at_hotmail.com> wrote:> >>>>>>>> Hello,> >>>>>>>>> >>>>>>>> I am relatively new to R and learning its ins and outs. As > >>>>>>>> part of a website I am building, I need to read and write > >>>>>>>> csv files directly from an SQL database. Basically I want to > >>>>>>>> convert R variables (dataframes) into CSV format, store them > >>>>>>>> as another R variable (as a properly formatted text string > >>>>>>>> suitable for csv reading) and then send this to one row in a > >>>>>>>> database.> >>>>>>>>> >>>>>>>> The SQL part is fine, the problem arises because I cannot > >>>>>>>> capture the output of write.csv! It posts to the terminal > >>>>>>>> !
 when file="" is used, however I also want to store it. Does > >>>>>>>> anyone have any ideas?> >>>>>>>>> >>>>>>>> Thanks in advance!> >>>>>>> >>>>>> --> >>>>>> Brian D. Ripley, ripley@stats.ox.ac.uk> >>>>>> Professor of Applied Statistics, http://www.stats.ox.ac.uk/ > >>>>>> ~ripley/> >>>>>> University of Oxford, Tel: +44 1865 272861 (self)> >>>>>> 1 South Parks Road, +44 1865 272866 (PA)> >>>>>> Oxford OX1 3TG, UK Fax: +44 1865 272595> >>>>>> >>>>> _________________________________________________________________> >>>>> Your Future Starts Here. Dream it? Then be it! Find it at > >>>>> www.seek.com.au> >>>>> http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fninemsn%2Eseek% > >>>>> 2Ecom%2Eau%2F%3Ftracking%3Dsk%3Ahet%3Ask%3Anine%3A0%3Ahot% > >>>>> 3Atext&_t=764565661&_r=OCT07_endtext_Future&_m=EXT> >>>>> >>>> --> >>>> Brian D. Ripley, ripley@stats.ox.ac.uk> >>>> Professor of Applied Statistics, http://www.stats.ox.ac.uk/ > >>>> ~ripley/> >>>> University of Oxford, Tel: +44 186!
 5 272861 (self)> >>>> 1 South Parks Road, +44 1865 272866 (PA)> >>>> O
xford OX1 3TG, UK Fax: +44 1865 272595> >>>> >>> _________________________________________________________________> >>> Your Future Starts Here. Dream it? Then be it! Find it at > >>> www.seek.com.au> >>> http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fninemsn%2Eseek% > >>> 2Ecom%2Eau%2F%3Ftracking%3Dsk%3Ahet%3Ask%3Anine%3A0%3Ahot% > >>> 3Atext&_t=764565661&_r=OCT07_endtext_Future&_m=EXT> >>> >> -- > >> Brian D. Ripley, ripley@stats.ox.ac.uk> >> Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/> >> University of Oxford, Tel: +44 1865 272861 (self)> >> 1 South Parks Road, +44 1865 272866 (PA)> >> Oxford OX1 3TG, UK Fax: +44 1865 272595> >> > > 
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