Tider & datum
R för medelnivå
Filip Schouwenaars
DataCamp Instructor
Idag, just nu!
today <- Sys.Date()
today
"2015-05-07"
class(today)
"Date"
now <- Sys.time()
now
"2015-05-07 10:34:52 CEST"
class(now)
"POSIXct" "POSIXt"
Skapa Date-objekt
my_date <- as.Date("1971-05-14")
my_date
"1971-05-14"
class(my_date)
"Date"
Skapa Date-objekt
my_date <- as.Date("1971-14-05")
Error: character string is not in a standard unambiguous format
my_date <- as.Date("1971-14-05", format = "%Y-%d-%m")
my_date
"1971-05-14"
Skapa POSIXct-objekt
my_time <- as.POSIXct("1971-05-14 11:25:15")
my_time
"1971-05-14 11:25:15 UTC"
Datumaritmetik
my_date
"1971-05-14"
my_date + 1
"1971-05-15"
my_date2 <- as.Date("1998-09-29")
my_date2 - my_date
Time difference of 10000 days
POSIXct-aritmetik
my_time
"1971-05-14 11:25:15 UTC"
my_time + 1
"1971-05-14 11:25:16 UTC"
my_time2 <- as.POSIXct("1974-07-14 21:11:55 UTC")
my_time2 - my_time
Time difference of 1157.407 days
Under huven
my_date
"1971-05-14"
unclass(my_date)
498
my_time
"1971-05-14 11:25:15 CET"
unclass(my_time)
43064715
attr(my_time, "tzone")
""
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