[R] stacking consecutive columns

[Claudia Beleites]

Dear Gregory,

> Is there an easier, cleaner way to do this?  Thanks.
There are of course several ways...

(assuming yearmonth to be a data.frame)

--- 1 ---

year <- colnames (yearmonth) [-1]
year <- gsub ("^[^[:digit:]]*([[:digit:]]*[^[:digit:]]*$)", "\\1", year)
year <- as.numeric (year)

month <- yearmonth$month

precip <- as.matrix (yearmonth [, -1])

long.df <- data.frame (month = rep (month, length (year)),
                        year = rep (year, each = nrow (yearmonth)),
                        precipitation = as.numeric (precip))


If you're about to do this more often:
--- 2 ---
package hyperSpec (outdated on CRAN, if you want to install it use the version 
on rforge)
has a function array2df which helps with this transformation:

long.df <- array2df (precip, label.x = "precipitation",
                      levels = list (month = month, year = year)

--- 3 ---
depending on your file (are the column names numbers without the Xs?)
you may be able to abuse a hyperSpec object to read your data easily:
x <- read.txt.wide ("filename", ...more options...)
then
as.long.df (x)
is about what you want.
(You'd probably want to rename the columns)

HTH Claudia

>
> Gregory A. Graves, Lead Scientist
> Everglades REstoration COoordination and VERification (RECOVER)
> Restoration Sciences Department
> South Florida Water Management District
> Phones:  DESK: 561 / 682 - 2429
>                     CELL:  561 / 719 - 8157
>
> ______________________________________________
> 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.


-- 
Claudia Beleites
Dipartimento dei Materiali e delle Risorse Naturali
Università degli Studi di Trieste
Via Alfonso Valerio 6/a
I-34127 Trieste

phone: +39 0 40 5 58-37 68
email: cbeleites at units.it