如何将日期和时间从字符转换为日期时间类型 [英] how to convert date and time from character to datetime type

问题描述

我将如何将它转换成一个保持日期和时间的日期时间类型对象？

hi how shall i convert this to a datetime type object which preserves both the date and the time?

DateTime="2007-02-01 00:00:00"

尝试

as.Date(DateTime,'%Y-%m-%d %H:%M:%S') 

但不返回时间部分。无法弄清楚在尝试strptime和lubridate之后。谢谢。

but doesn't returns the time part. couldn't figure out how after trying strptime and lubridate. thanks.

推荐答案

As @Richard Scriven指出，你不应该使用 as.Date ，因为它不是一个 datetime 类。以下是几种不同的方法：

As @Richard Scriven pointed out, you shouldn't be using as.Date because it's not a datetime class. Here are a few different ways:

DateTime <- "2007-02-01 00:00:00"
DateTime2 <- "02/01/2007 00:06:10"
## default format Y-m-d H:M:S
> as.POSIXct(DateTime,tz=Sys.timezone())
[1] "2007-02-01 EST"
> as.POSIXlt(DateTime,tz=Sys.timezone())
[1] "2007-02-01 EST"
##
## specify format m/d/Y H:M:S
> as.POSIXct(DateTime2,format="%m/%d/%Y %H:%M:%S",tz=Sys.timezone())
[1] "2007-02-01 00:06:10 EST"
> as.POSIXlt(DateTime2,format="%m/%d/%Y %H:%M:%S",tz=Sys.timezone())
[1] "2007-02-01 00:06:10 EST"
##
## using lubridate
library(lubridate)
> ymd_hms(DateTime,tz=Sys.timezone())
[1] "2007-02-01 EST"
> mdy_hms(DateTime2,tz=Sys.timezone())
[1] "2007-02-01 00:06:10 EST"

您不必为 as.POSIXct 指定 format = 和 as.POSIXlt 当您有％Y-％m-％d％H：％M：％S 格式。在其他情况下，如％m /％d /％Y％H：％M：％S ，您通常必须明确指定格式。

You don't have to specify format= for as.POSIXct and as.POSIXlt when you have the %Y-%m-%d %H:%M:%S format. In other cases, like %m/%d/%Y %H:%M:%S, you usually have to specify the format explicitly.

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