[R] help with data.frame

Andras Farkas motyocska at yahoo.com
Tue May 21 20:01:23 CEST 2013


Dear All

I have the following code for list "a":

a <-list(structure(c(0, 4, 8, 12, 0, 19.5581076131386, 10.7499105081144, 
5.91923975728553, 0, 4.08916328337685, 2.26872955281708, 1.24929641535359
), .Dim = c(4L, 3L), .Dimnames = list(NULL, c("time", "y", "b"
)), istate = c(2L, 107L, 250L, NA, 5L, 5L, 0L, 52L, 22L, NA, 
NA, NA, NA, 0L, 1L, 1L, NA, NA, NA, NA, NA), rstate = c(0.867511261090201, 
0.867511261090201, 12.7772879103809, 0, 0), lengthvar = 2L, class = c("deSolve", 
"matrix"), type = "lsoda"), structure(c(0, 4, 8, 12, 0, 17.0238115689622, 
9.02425032330714, 4.7893314106951, 0, 4.45067278743554, 2.37140075611636, 
1.25855947034654), .Dim = c(4L, 3L), .Dimnames = list(NULL, c("time", 
"y", "b")), istate = c(2L, 106L, 251L, NA, 4L, 4L, 0L, 52L, 22L, 
NA, NA, NA, NA, 0L, 1L, 1L, NA, NA, NA, NA, NA), rstate = c(0.662055762167652, 
0.662055762167652, 12.3096826617166, 0, 0), lengthvar = 2L, class = c("deSolve", 
"matrix"), type = "lsoda"), structure(c(0, 4, 8, 12, 0, 15.3548797334796, 
8.17712839316703, 4.36718847853436, 0, 5.15624657530424, 2.77411694866808, 
1.48166036763212), .Dim = c(4L, 3L), .Dimnames = list(NULL, c("time", 
"y", "b")), istate = c(2L, 108L, 260L, NA, 5L, 5L, 0L, 52L, 22L, 
NA, NA, NA, NA, 0L, 1L, 1L, NA, NA, NA, NA, NA), rstate = c(0.735884123193699, 
0.735884123193699, 12.1878866053931, 0, 0), lengthvar = 2L, class = c("deSolve", 
"matrix"), type = "lsoda"))

then I convert it to "b"

b <-data.frame(a)

and manually I would extract the y variables (y, y.1 and y.2) as follows

d <-t(cbind(b$y,b$y.1,b$y.2))

Currently I only have 3 y variables, so manual solution is very easy. I would like to ask if you have any thoughts on how I could "automate" (or extract all ys) this so that I could achieve the same goal even if I have 5000 ys (from y, y.1, y.2.... to y.5000) or any other number of ys for that matter with a simple code (as opposed to something like d <-t(cbind(b$y,b$y.1,b$y.2,....b$y.5000))).

your help is greatly appreciated,

thanks,

Andras



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