R/datesByDay.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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# For each valid day in validDays, generate the start dates/time of each valid day
# Returns a data frame - the date/time string values of each day
datesByDay <- function(validDays) {

	dates = c()

	# column names for each date/time string value we generate	
	cnames = c()

	count=1

	# for each valid day, get the first date/time of the day
	for (vd in validDays) {
		
		# date/time of the start of this day
		glucoseThis = vd@glucose
		dateVD = format(glucoseThis$time[1], "%Y-%m-%d %H:%M:%S %Z")

		dates = append(dates, dateVD)
		cnames = append(cnames, paste("datetime_start_day", count, sep=""))

                count=count+1
	}

	# set column names for date values
	res = rbind(dates)
	colnames(res) = cnames

	return(res)
}