R/seqn_by.R

In yikeshu0611/nhanesR: Tools for "NHANES" Database

seqn_by <- function(x,by){
    bylist <- lapply(by, nchar)
    names(bylist) <- by
    de <- unique(nchar(by)) |> do::decrease()
    for (i in 1:length(de)) {
        ck <- sapply(by,function(j) nchar(j) ==de[i])
        xi <- by[ck]
        for (j in 1:length(xi)) {
            ckj <- do::left(x,nchar(xi[j])) == xi[j]
            bylist[[xi[j]]] <- x[ckj]
            x <- x[!ckj]
        }
    }
    xn <- bylist|> unlist()
    names(xn) <- NULL
    xn
}