[Gretl-users] Re: string to epoch

I was playing with the nice COVID international data set available at https://github.com/owid/covid-19-data/tree/master/public/data The csv file contains a "date" column, that gretl reads as a string-valued series. In order to turn it into proper dates, I ended up writing this little function that turns a string valued series holding dates into a numeric string holding the epoch day. The requisite is that the string is organised as year-month-day, with an arbitrary delimiter that must be passed as the optional second parameter to the function (default: dash). <hansl> function series str2epoch(series s, string delimiter[null]) strings datestrs = strvals(s) scalar n = nelem(datestrs) fmt = "%d-%d-%d" if exists(delimiter) fmt = strsub(fmt, "-", delimiter) endif scalar y m d matrix ymd = seq(1,n)' ~ zeros(n, 3) loop i = 1 .. n s_i = datestrs[i] sscanf(s_i, fmt, y, m, d) ymd[i,2:] = {y,m,d} endloop series s_y = replace(s, ymd[,1], ymd[,2]) series s_m = replace(s, ymd[,1], ymd[,3]) series s_d = replace(s, ymd[,1], ymd[,4]) return epochday(s_y, s_m, s_d) end function </hansl>