시간 및 날짜
중급 R
Filip Schouwenaars
DataCamp Instructor
오늘, 바로 지금!
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"
날짜 객체 만들기
my_date <- as.Date("1971-05-14")
my_date
"1971-05-14"
class(my_date)
"Date"
날짜 객체 만들기
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"
POSIXct 객체 생성
my_time <- as.POSIXct("1971-05-14 11:25:15")
my_time
"1971-05-14 11:25:15 UTC"
날짜 연산
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 산술 연산
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
내부 동작
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")
""
전용 R 패키지
lubridatezooxts
연습해 봅시다!
중급 R
