[R] adressing dataframes

[David Winsemius]

I have not figured out why you seem so attached to the c(type)  
strategy but try:

> numbers <-summary(rawdata[ , c(type)] )


On Jun 16, 2009, at 12:06 PM, John Fitzgerald wrote:

>
> Hi everyone,
>
> I experience some problems with adressing of data.frames when I  
> retrieve
> some information for geographical position (ypos, xpos) ot of a MySQL
> Database and want to perform some simple statistics. The problem is
> adressing the dataframes with a construct like
>
> rawdata[c(type)] vs. rawdata$TEMPMIN
>
>
> to retrieve the numerical information and not a string (I want to  
> store the
> numerical values in a database for graphical expression)
>
>
>
> Code Snippet:
>
> type <- "TEMPMIN"
>
> numbers <-summary(rawdata[c(type)])
> numbers2 <- summary(rawdata$TEMPMINIMUM)
>
>
>
> Results:
>
>
> numbers
>    TEMPMIN
> Min.   :-7.200
> 1st Qu.: 2.100
> Median : 6.200
> Mean   : 6.588
> 3rd Qu.:11.800
> Max.   :18.100
>
>> numbers[[1]]
> [1] "Min.   :-7.200  "       <<< which is a string
>
>
>
> Whereas:
>
>> numbers2
>   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
> -7.200   2.100   6.200   6.588  11.800  18.100
>
>> numbers2[[1]]
> [1] -7.2          <<<< which is a numerical value (and can be easily  
> be
> saved in a db)
>
>
>
> I've tried some conversions like (as.matrix, as.list,  
> as.data.frame...), but
> still, using the c() construct will change the results of summary() to
> strings. The same happens with median()....
>
>
>
>
> Kind regards,
>
> John Fitzgerald
>
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT