[R] Two last questions: about output

[Ted Byers]

Thanks Gabor,

I get how to make a frame using existing vectors.  In my example, the
following puts my first three columns into a frame (and displays it:

> testframe <- data.frame(mid=V1,year=V2,week=V3)
> testframe
   mid year week
1  251 2008   18
2  251 2008   19
3  251 2008   20
4  251 2008   22
5  251 2008   23
6  251 2008   24
7  251 2008   25

I show the first of about 60 rows, and I am pleased that these values
appear as integers.

But what I don't see is how to add the fp$estimate,fp$sd values
obtained from my analyses to vectors to form the last two columns in
the data frame.  Is there something like a vector type, analogous to
the vector class std::vector from C++, that has a push_back function
allowing a vector to grow as new values are generated?

And suppose I have the following table in MySQL (ignoring for the
moment keys and indeces):

CREATE TABLE (
  id INTEGER  UNSIGNED NOT NULL auto_increment,
  mid INTEGER NOT NULL,
  y  INTEGER NOT NULL,
  w INTEGER NOT NULL,
  rate DOUBLE NOT NULL,
  sd DOUBLE NOT NULL
  process_date DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
) ENGINE=InnoDB;

How would I tell dbWriteTable() that my frame's five columns
correspond to mid,y,w,rate and sd in that order, and that the fields
id and process_date will take the appropriate default values?  Or do I
need a temporary table, in memory, that has only the five columns, and
use a stored procedure to move the data to its final home?

Thanks again,

Ted


On Wed, Oct 15, 2008 at 9:57 PM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> Put the data in an R data frame and use dbWriteTable() to
> write it to your MySQL database directly.
>
> On Wed, Oct 15, 2008 at 9:34 PM, Ted Byers <r.ted.byers at gmail.com> wrote:
>>
>> Here is my little scriptlet:
>>
>> optdata =
>> read.csv("K:\\MerchantData\\RiskModel\\AutomatedRiskModel\\soptions.dat",
>> header = FALSE, na.strings="")
>> attach(optdata)
>> library(MASS)
>> setwd("K:\\MerchantData\\RiskModel\\AutomatedRiskModel")
>> for (i in 1:length(V4) ) {
>>   x = read.csv(as.character(V4[[i]]), header = FALSE, na.strings="");
>>   y = x[,1];
>>   fp = fitdistr(y,"exponential");
>>   print(c(V1[[i]],V2[[i]],V3[[i]],fp$estimate,fp$sd))
>> }
>>
>>
>> And here are the first few lines of output:
>>
>>                                               rate         rate
>> 2.510000e+02 2.008000e+03 1.800000e+01 6.869301e-02 6.462095e-03
>>                                               rate         rate
>> 2.510000e+02 2.008000e+03 1.900000e+01 5.958023e-02 4.491029e-03
>>                                               rate         rate
>> 2.510000e+02 2.008000e+03 2.000000e+01 8.631714e-02 7.428996e-03
>>                                               rate         rate
>> 2.510000e+02 2.008000e+03 2.200000e+01 1.261538e-01 1.137491e-02
>>                                               rate         rate
>> 2.510000e+02 2.008000e+03 2.300000e+01 1.339523e-01 1.332875e-02
>>                                               rate         rate
>> 2.510000e+02 2.008000e+03 2.400000e+01 8.916084e-02 1.248501e-02
>>
>> There are only two things wrong, here.
>>
>> 1) the first three columns are integers, and are output variously as
>> integers, floating point numbers and, as shown here, in scientific notation.
>> 2) this output isn't going to a file or to my DB.  This second issue isn't
>> much of a problem, as I think I know now how to deal with it.
>>
>> This output data is, in one sense, perfectly organized, and there is a table
>> with a nearly identical structure (these five columns, plus one to hold the
>> date on which the analysis is performed (and of course, therefore, it has a
>> default value of the current timestamp  - handled in MySQL).  If I can get
>> the data written to a CSV file, with the first three columns provided as
>> integers, I can use the DB's bulk load utility to get the data into the DB,
>> and this may be faster than having this scriptlet connecting directly to the
>> DB to insert the data (unless the DBI has a function for a bulk load that
>> helps here).
>>
>> Any idea how best to handle my formatting problem here?
>>
>> Thanks
>>
>> Ted
>> --
>> View this message in context: http://www.nabble.com/Two-last-questions%3A-about-output-tp20005519p20005519.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
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>>
>