[R] what exactly is the dim of data set yarn in package "pls"?

[William Dunlap]

Start by using str() to get an idea of the structure of this dataset

   > str(pls::yarn)
   'data.frame':   28 obs. of  3 variables:
    $ NIR    : num [1:28, 1:268] 3.07 3.07 3.08 3.08 3.1 ...
     ..- attr(*, "dimnames")=List of 2
     .. ..$ : NULL
     .. ..$ : NULL
    $ density: num  100 80.2 79.5 60.8 60 ...
    $ train  : logi  TRUE TRUE TRUE TRUE TRUE TRUE ...

I.e., it contains 3 things, each with 28 observations: a 268-column
matrix of numbers, NIR, a numeric vector, density, and a logical
vector, train.  data.frames can contain matrices. They are not common,
but can be used for grouping purposes or because it is easier to
refer to NIR[,j] than paste(NIR, j, sep=".").

help(yarn) tells about the meaning of the components.

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
> Of C W
> Sent: Saturday, October 06, 2012 6:45 PM
> To: r-help
> Subject: [R] what exactly is the dim of data set yarn in package "pls"?
> 
> Hi list,
> I am looking at the data yarn in package, I don't understand what is
> dimension of this data set.
> 
> I did the following:
> > library(pls)
> 
> > data(yarn)
> 
> > dim(yarn)
> 
> [1] 28  3
> 
> > head(yarn)
> 
>     NIR.1   NIR.2   NIR.3   NIR.4   NIR.5   NIR.6   NIR.7   NIR.8   NIR.9
> NIR.10  NIR.11
> 
> 1 3.06630 3.08610 3.10790 3.09720 2.99790 2.82730 2.62330 2.40390 2.19310
> 2.00580 1.83790
> 
> 2 3.06750 3.08570 3.09580 3.06920 2.98180 2.84080 2.67600 2.50590 2.35060
> 2.22300 2.11920
> 
> 3 3.07500 3.09660 3.09160 3.02880 2.88490 2.68850 2.47640 2.26940 2.08240
> 1.91950 1.77470
> 
> 4 3.08280 3.09730 3.10100 3.07350 2.99130 2.87090 2.73920 2.61020 2.50000
> 2.42370 2.37740
> 
> 5 3.10290 3.10340 3.08480 3.02280 2.89270 2.71590 2.53840 2.37640 2.23970
> 2.13460 2.05340
> 
> 6 3.08150 3.08490 3.04870 2.93050 2.73230 2.50890 2.29440 2.09950 1.93280
> 1.79250 1.66930
> 
> There were 270 columns, I only copy pasted the first 11 columns.  But
> either way, this is NOT 3 columns.
> 
> Could anyone let me know what is wrong here?
> 
> Thanks in advance,
> Mike
> 
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