R/save.var.R

In varhandle: Functions for Robust Variable Handling

## Function Description:
##     This function gets a list of variables as a character vector and save
##     each variable name in a separate file, so that they can be loaded
##     separately.

save.var <- function(varlist = ls(envir = as.environment(.GlobalEnv)),
                     path = getwd(), newdir = TRUE, newdirtag = NULL,
                     envir = .GlobalEnv){
    #----[ checking input ]----#
    {
        ## Check the envir attribute
        if (!is.environment(envir)) {
        	stop("You should specify an existing environment")
        }

        ## check the varlist attribute
        # Check if the varlist is empty, show error and mention default
        if (!length(varlist)) {
           stop("The varlist parameter should contain an existing variable.")
        }
        
        # If the varlist has a name that is not in ls(), show error with the location of bad variable name
        if (sum(is.element(varlist, ls(envir = as.environment(envir)))) != length(varlist)) {
            bad_var_location <- which(is.element(varlist, ls()) == FALSE)
            stop(paste("All the items in the varlist should be a real existing variable.\nThe item number", bad_var_location, "is not among variables of selected environment!\n", sep=" "))
        }

        ## check the path attribute
        # The path should be a vector of size one and the folder should exist
        if (length(path) != 1) {
        	stop("The path attribute should be a vector with length 1.")
        }
        # checking if the path exists
        if (!file.exists(path)) {
        	stop("The directory path should fully exist. Please use a correct existing path.")
        }

        ## check the newdir attribute
        if (newdir != TRUE & newdir != FALSE) {
        	stop("The newdir attribute only accepts TRUE or FALSE as input.")
        }

        ## check newdirtag attribute
        if (length(newdirtag)) {
        	# The newdirtag should be a vector of size one
        	if (length(newdirtag) != 1) {
        		stop("The newdirtag attribute should be a vector with length 1.")
        	}
        	# If the newdirtag was empty or contained more than 240 character
            if (nchar(newdirtag) > 240) {
        	    stop("The acceptable number of characters for newdirtag attribute is 1 up to 240.")
            }
        }
    }


    #----[ create new directory ]----#
    {
        # if user wants them in new directory
        if (newdir == TRUE) {
        	# Getting time
        	time.now <- format(Sys.time(), "%Y%m%d-%H%M%S")
        	if (length(newdirtag)) {
        		# Create new folder name with tag
        		final.dir <- paste(time.now, "-", newdirtag, sep = '')
        	}else{
        		# Create new folder name without tag
        		final.dir <- time.now
        	}
            # create the cirectory in the correct path
        	dir.create(file.path(path, final.dir))
        }else{
            # if user do not want to create a new folder, define the final folder as the path itself
            final.dir <- ""
        }

    }


    #----[ save variables ]----#
    {
        # Write variables one by one in separate files.
        for (i in varlist) {
            save(file = file.path(path, final.dir, paste0(i, ".RData")), list = i, envir = envir)
        }
    }


}