[R] Accessing DF index

[David Winsemius]

On Feb 19, 2011, at 4:50 PM, eric wrote:

>
> I have a dataframe called x2. It seems to have a date column but I  
> can't
> access it or give it a name or convert it to a date. How do I refer  
> to that
> first column and make it a date ? When I try x2[1,] I get the second  
> column.

It is not actually a column but is rather a set of row names:

?rownames

rownames(x2)


>
> head(x2)
>                  FAIRX        SP500        delta
> 2000-08-31  0.010101096  0.007426964  0.002674132
> 2000-09-29  0.096679730 -0.054966292  0.151646023
> 2000-10-31 -0.008245580 -0.004961785 -0.003283795
> 2000-11-30  0.037024545 -0.083456134  0.120480679
> 2000-12-29  0.080042708  0.004045193  0.075997514
> 2001-01-31 -0.009042396  0.034050246 -0.043092643
>
> x[1,1]
>                FAIRX
> 2000-08-31 0.01010110
>
> x[1,2]
>                 SP500
> 2000-08-31 0.007426964
>
> str(x2)
> 'data.frame':	127 obs. of  3 variables:
> $ FAIRX: num  0.0101 0.09668 -0.00825 0.03702 0.08004 ...
> $ SP500: num  0.00743 -0.05497 -0.00496 -0.08346 0.00405 ...
> $ delta: num  0.00267 0.15165 -0.00328 0.12048 0.076 ..
> -- 
> View this message in context: http://r.789695.n4.nabble.com/Accessing-DF-index-tp3314649p3314649.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> 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.

David Winsemius, MD
West Hartford, CT