R/nhs_wt.R

In yikeshu0611/nhanesR: Tools for "NHANES" Database

#' calculate cominbe weight
#'
#' @param data data
#' @param yr2 weight for 2 years
#' @param yr4 weight for 4 years: 1999-2000 and 2001-2002
#' @param wtname name for combine weight column
#'
#' @return combine weight
#' @export
#'
nhs_wt <- function(data,yr2,yr4,wtname='cwt'){
    (cycle <- length(unique(data$Year)))
    if (missing(yr4)){
        cwt <- data[,yr2]*1/cycle
        eval(parse(text=sprintf('data$%s <- cwt',wtname)))
    }else{
        ck <- data$Year %in% prepare_years(1999:2001)
        cwt <- ifelse(ck,data[,yr4]*2/cycle,data[,yr2]*1/cycle)
        eval(parse(text=sprintf('data$%s <- cwt',wtname)))
    }
    return(data)
}