我正在从UCI处理本地化数据用于个人活动数据集数据集,在这个数据集中有一列日期和时间(一列),格式如下:
I am working on "Localization Data for Person Activity Data Set" dataset from UCI and in this data set there is a column of date and time(both in one column) with following format:
27.05.2009 14:03:25:777 27.05.2009 14:03:25:183 27.05.2009 14:03:25:210 27.05.2009 14:03:25:237 ...我想知道是否有使用R将此列转换为时间戳。
I am wondering if there is anyway to convert this column to timestamp using R.
推荐答案首先,我们需要将从毫秒到毫秒的冒号分隔开来,否则最后一步将不起作用(感谢 Dirk Eddelbuettel )因为最终R将使用它想要的分隔符,要更快,我会继续,替换所有的冒号点:
First of all, we need to substitute the colon separating the milliseconds from the seconds to a dot, otherwise the final step won't work (thanks to Dirk Eddelbuettel for this one). Since in the end R will use the separators it wants, to be quicker, I'll just go ahead and substitute all the colons for dots:
x <- "27.05.2009 14:03:25:777" # this is a simplified version of your data y <- gsub(":", ".", x) # this is your vector with the aforementioned substitution顺便说一下,这是你的矢量应该照顾 gsub :
By the way, this is how your vector should look after gsub:
> y [1] "27.05.2009 14.03.25.777"现在,为了它显示毫秒,您首先需要调整R选项,然后使用一个名为 strptime 的函数,这将将您的日期向量转换为POSIXlt(一个R友好的)格式。只需执行以下操作:
Now, in order to have it show the milliseconds, you first need to adjust an R option and then use a function called strptime, which will convert your date vector to POSIXlt (an R-friendly) format. Just do the following:
> options(digits.secs = 3) # this tells R you want it to consider 3 digits for seconds. > strptime(y, "%d.%m.%Y %H:%M:%OS") # this finally formats your vector [1] "2009-05-27 14:03:25.777"我学到了这个很棒的技巧这里。 另一个答案也表示您可以跳过选项设置并使用,例如, strptime(y,%d。%m。%Y%H:%M:%OS3),但对我来说不起作用。 Henrik 指出,功能的帮助页面?strptime 指出,%OS3 位是与操作系统相关的。我正在使用更新的Ubuntu 13.04,并使用%OS3 产生 NA 。
I've learned this nice trick here. This other answer also says you can skip the options setting and use, for example, strptime(y, "%d.%m.%Y %H:%M:%OS3"), but it doesn't work for me. Henrik noted that the function's help page, ?strptime states that the %OS3 bit is OS-dependent. I'm using an updated Ubuntu 13.04 and using %OS3 yields NA.
使用 strptime (或其他与POSIX相关的功能,如 as.Date )时,请保留考虑到使用的一些最常用的转换(根据 DWin 的建议,为了简洁而进行编辑。完整列表 strptime ):
When using strptime (or other POSIX-related functions such as as.Date), keep in mind some of the most common conversions used (edited for brevity, as suggested by DWin. Complete list at strptime):
- %a 当前语言环境中的缩位工作日名称。
- %A 当前区域的全部工作日名称。
- %b 当前区域设置中的缩写月份名称。
- %B 当前区域设置中的全月份名称。 >
- %d 以十进制数(01-31)为单位的日期。
- %H 小时数为十进制数(00-23)。时间如24:00:00接受输入。
- %I 小时数为十进制数(01-12)。
- %j 年份为十进制数(001-366)。
- %m 十进制数月份(01-12)
- %M 分钟作为十进制数(00-59)。
- %p 本地区的AM / PM指标。与%I 而不是与%H 。
- ` %S第二个十进制数(00-61),允许最多两个闰秒(但POSIX兼容的实现将忽略闰秒)。
- % U 使用星期日作为十进制数(00-53)的一周中的星期,作为一周的第一天(通常为第一周的第1个星期日)。
- %w 平日为十进制数(0-6,星期日为0)
- %W 使用星期一作为十进制数(00-53)的一周中的星期几(通常与当年的第一个星期一)作为第1周的第1天)。
- %y 没有世纪的年份(00-99)。在输入上,值00至68的前缀为20和69至99之间。19
- %Y 具有世纪的年份。请注意,虽然原始公历中没有零,但ISO 8601:2004定义为有效(解释为1BC)
- %a Abbreviated weekday name in the current locale.
- %A Full weekday name in the current locale.
- %b Abbreviated month name in the current locale.
- %B Full month name in the current locale.
- %d Day of the month as decimal number (01–31).
- %H Hours as decimal number (00–23). Times such as 24:00:00 are accepted for input.
- %I Hours as decimal number (01–12).
- %j Day of year as decimal number (001–366).
- %m Month as decimal number (01–12).
- %M Minute as decimal number (00–59).
- %p AM/PM indicator in the locale. Used in conjunction with %I and not with %H.
- `%S Second as decimal number (00–61), allowing for up to two leap-seconds (but POSIX-compliant implementations will ignore leap seconds).
- %U Week of the year as decimal number (00–53) using Sunday as the first day 1 of the week (and typically with the first Sunday of the year as day 1 of week 1). The US convention.
- %w Weekday as decimal number (0–6, Sunday is 0).
- %W Week of the year as decimal number (00–53) using Monday as the first day of week (and typically with the first Monday of the year as day 1 of week 1). The UK convention.
- %y Year without century (00–99). On input, values 00 to 68 are prefixed by 20 and 69 to 99 by 19
- %Y Year with century. Note that whereas there was no zero in the original Gregorian calendar, ISO 8601:2004 defines it to be valid (interpreted as 1BC)
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