r - Sampling package - strange behaviour of strata function -

in function strata declare numer of units drawn each stratum , after executing strange result. numer of units different declared.

here example:

library(sampling) data(swissmunicipalities) st=strata(swissmunicipalities,stratanames=c("reg"),size=c(30,20,45,15,20,11,44),method="srswor")  

result:

> table(st$reg)  1   2   3  4   5    6  7  20 15 45 30 20 11 44  

should be:

30,20,45,15,20,11,44 

i grateful anwsers.

if read page of strata function, have :

size: vector of stratum sample sizes (in order in       strata given in input data set). 

let's check order in numbers in reg variable

require(sampling) data(swissmunicipalities) swiss <- swissmunicipalities unique(swiss$reg) ## [1] 4 1 3 2 5 6 7 

as can see not naturally orderered, have 2 options.

first options, write size in same order original data.

size <- c(15, 30, 45, 20, 20, 11, 44) st <- strata(swiss, stratanames = "reg", size = size, method = "srswor") table(st$reg) ##  1  2  3  4  5  6  7  ## 30 20 45 15 20 11 44 

second option, order data first , keep size first wrote it

swiss <- swiss[order(swiss$reg), ] st <- strata(swiss, stratanames = "reg", size = c(30, 20, 45, 15, 20, 11, 44),  method = "srswor") table(st$reg) ##  1  2  3  4  5  6  7  ## 30 20 45 15 20 11 44