R/fnAppend.R

In NMdata: Preparation, Checking and Post-Processing Data for PK/PD Modeling

##' paste something before file name extension.
##' 
##' Append a file name like file.mod to file_1.mod or file_pk.mod. If
##' it's a number, we can pad some zeros if wanted. The separator
##' (default is underscore) can be modified.
##' @param fn The file name to modify
##' @param x A character string or a numeric to add to the file name
##' @param pad0 In case x is numeric, a number of zeros to pad before
##'     the appended number. This is useful if you are generating say
##'     more than 10 files, and your counter will be 01, 02,..,
##'     10,... and not 1, 2,...,10,...
##' @param sep The separator between the existing file name (until
##'     extension) and the addition.
##' @return A character (vector)
##'
##' @export


fnAppend <- function(fn,x,pad0=0,sep="_"){
    
    if((!is.numeric(x)&&!is.character(x)) ||length(x)!=1) stop("x must be numeric or character vector of length 1.")

    fnroot <- sub("^(.+)\\..+$","\\1",fn)
    fnext <- sub(".*\\.([^\\.]+)$","\\1",fn)
    
    if(is.numeric(x)){
        string <- sprintf(fmt=paste("%0",pad0,"d",sep=""),x)
    } else {
        string <- x
    }
    if(nchar(string)>0){
        paste0(fnroot,sep,string,".",fnext)
    } else {
        fn
    }
    
}