第十二章 时间
bd <- '1994-09-22 20:30:00'
bdtime <- strptime(x = bd, format = '%Y-%m-%d %H:%M:%S',
tz = "Asia/Shanghai")
bdtime
class(bd)
class(bdtime)
t1 <- Sys.time() # 返回当前时刻
t2 <- date() # 返回当前时刻
t3 <- Sys.Date() # 返回当前日期
t1
t2
t3
class(t1)
class(t2)
class(t3)
bdtime$wday
unlist(unclass(bdtime))
format(bdtime, format = '%d.%m.%Y')
bdtime + 1
bdtime + 60
bdtime + 3600
t3 <- bdtime + 86400
t3
bdtime2 <- strptime(
'1995-09-01 7:30', format = '%Y-%m-%d %H:%M',
tz = 'Asia/Shanghai')
bdtime2 - bdtime
difftime(time1 = bdtime2, time2 = bdtime, units = 'secs')
mean(c(bdtime, bdtime2))
(a <- strptime("2018-03-25 03:00:00",
format = "%Y-%m-%d %H:%M:%S", tz = "CET"))
a - 1
(a <- as.POSIXlt("2018-03-25 03:00:00", tz = "CET"))
a - 1
(a <- as.POSIXlt("2018-03-25 02:00:00", tz = "CET"))
(a <- strptime("2018-03-25 02:00:00",
format = "%Y-%m-%d %H:%M:%S", tz = "CET"))
a - 1