[R] Bootstrap encounter histories data

[Rui Barradas]

Hello,

One more thing, if you have the data as strings of states/space/group, 
you can split it in vectors state/group with

# This is your data example
x <- c(
"1100222101 1",
"0000020010 3",
"0010101022 2"
)

mat <- do.call(rbind, strsplit(x, " "))


But this creates a matrix, so you'll need to revise the function as

fun <- function(x){
	f <- function(y){
		idx <- sample(NROW(y), NROW(y), replace = TRUE)
		y[idx, ]
	}
	sp <- split(as.data.frame(x), x[, 2])
	res <- do.call(rbind, lapply(sp, f))
	rownames(res) <- seq_len(nrow(res))
	res
}

fun(mat)


Hope this helps,

Rui Barradas

Em 14-03-2013 11:34, Rui Barradas escreveu:
> Hello,
>
> It doesn't seem very complicated.
> First of all, for the function fun below to work, you need the data not
> as strings of staes followed by a space followed by a broup number, but
> in two columns vectors, a character vector of states and a vector of
> groups. The vector of groups can be of class character, factor or
> numeric. I've written a function to simulate such data.
>
>
> makeData <- function(n, g = 3, size = 10){
>      res <- matrix(0, nrow = n, ncol = size)
>      gr <- sample(g, n, replace = TRUE)
>      for(i in seq_len(n))
>          res[i, ] <- sample(0:2, 10, replace = TRUE, prob = c(0.5, 0.25,
> 0.25))
>      res <- apply(res, 1, paste0, collapse = "")
>      data.frame(states = res, group = gr, stringsAsFactors = FALSE)
> }
>
> dat <- makeData(10)
>
> # Now to sample from 'dat', by group.
> fun <- function(x){
>      f <- function(y){
>          idx <- sample(nrow(y), nrow(y), replace = TRUE)
>          y[idx, ]
>      }
>      res <- do.call(rbind, lapply(split(x, x[, 2]), f))
>      rownames(res) <- seq_len(nrow(res))
>      res
> }
>
> fun(dat)
>
>
> Hope this helps,
>
> Rui Barradas
>
> Em 14-03-2013 10:25, Simone Santoro escreveu:
>>
>> Hi all,
>>
>> I am working with a capture-recapture analyses and my data set
>> consists of a
>> typical set of encounter histories.
>> Thus, for each individual I have a string (same length for all the
>> individuals) consisting of 0 (not seen) and other numbers (seen in state
>> "1", seen in state "2", etc. where state may refer to breeding, nesting,
>> feeding, etc.).
>> At the end of each string I have a last value that refers to the group
>> (according to sex, age, sex*age, whatever). State and group refer to
>> different classifications.
>> Hence my original data set would be (by the way I can modify it to make
>> things easier):
>> 0001002002 1; (individual of group 1, first captured in state "1! at
>> occasion 4th, not captured at occasion 5th and 6th, captured at 7th in
>> state
>> 2...etc.)
>> 1100222101 1;
>> 0000020010 3;
>> 0010101022 2;
>> ...
>>
>> Suppose I have 5000 strings divided in x individuals of group 1, y
>> individuals of group 2, ... z individuals of group "n".
>> I need to bootstrap this data set to get a new data set of the same
>> length
>> (resampling with replacement) and where the number of individuals of each
>> group is maintained the same.
>>
>> Does anyone have an idea on how to do it?
>> Thanks in advance for any help
>>
>> Simone
>>
>>
>>
>>
>>
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/Bootstrap-encounter-histories-data-tp4661300.html
>>
>> Sent from the R help mailing list archive at Nabble.com.
>>
>>
>>     [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> 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.
>>
>
> ______________________________________________
> 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.