R/getUserIDFromFileName.R

In MRCIEU/GLU: Derives Summary Variables from Continuous Glucose Monitoring (CGM) data

# The MIT License (MIT)
# Copyright (c) 2018 Louise AC Millard, MRC Integrative Epidemiology Unit, University of Bristol
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# Extracts user ID from file name of the format: data_export-[USERID].csv
# Returns user ID value
getUserIDFromFileName <- function(f) {

        userID = unlist(strsplit(f, "data_export-"))[2]
        userID = unlist(strsplit(userID, "\\."))[1]

	# if not medtronic format then use file name as the participant ID
	if (is.na(userID)) {
		userID = sub('\\..*$', '', f) 
	}

        return(userID)
}