guess_formats + R + lubridate [英] guess_formats + R + lubridate

问题描述

我在理解如何在lubridate中使用guess_formats函数时遇到麻烦.我有一些未知的日期/格式顺序的日期向量.我想将它们转换为Date对象(或至少转换尽可能多的对象).以下代码是我尝试过的:

I'm having trouble understanding how to use the guess_formats function in lubridate. I have a vector of dates in some unknown set/order of formats. I'd like to convert them to a Date object (or at least convert as many as possible). The following code is what I've tried:

library(lubridate)
sampleDates <- c("4/6/2004","4/6/2004","4/6/2004","4/7/2004",
        "4/6/2004","4/7/2004","2014-06-28","2014-06-30","2014-07-12",
        "2014-07-29","2014-07-29","2014-08-12")
formats <- guess_formats(sampleDates, c("Ymd", "mdY"))
dates <- as.Date(sampleDates, format=formats)

这给出了所有NA.

这显然只是一个简短的例子.在实际情况下，我不知道各种格式的分散位置，也不会100％确定只有％m/％d/％Y和％Y-％m-％d.有人可以让我知道A.在此示例中如何使用guess_formats或B.在lubridate/base R中是否有更适合使用的东西，希望没有大量的正则表达式.谢谢！

This is obviously just a short example. In the real case, I wouldn't know where the various formats are scattered about, and I wouldn't be 100% sure there are only %m/%d/%Y and %Y-%m-%d. Could someone let me know either A. how would guess_formats be used in this example or B. is there something more appropriate to use in lubridate/base R, hopefully without a lot of regex'ing. Thanks!

我也尝试过parse_date_time.我不了解此示例的以下工作:

I've also tried parse_date_time. What I don't understand is the following works for this example:

parse_date_time(sampleDates,
            orders = c("Ymd", "mdY"),
            locale = "eng")

但这不是:

parse_date_time(sampleDates,
            orders = c("mdY", "Ydm"),
            locale = "eng")

在我的实际数据集中，我不知道格式化的顺序，这对于该功能而言似乎很重要.

In my actual set of data, I will not know the order of the formatting, which seems to be important for this function.

双重Dur，好的，我看到在第一个parse_date_time示例中有Ymd，在第二个parse_date_time示例中有Ydm....

Double Dur, OK, I see I had Ymd in the first parse_date_time example and Ydm in the second...carry on.

推荐答案

无需调用guess_formats，只需使用parse_date_time即可:

No need to call guess_formats just use parse_date_time :

 parse_date_time(sampleDates, c("Ymd", "mdY"))

 [1] "2004-04-06 UTC" "2004-04-06 UTC" "2004-04-06 UTC" "2004-04-07 UTC" "2004-04-06 UTC"
 [6] "2004-04-07 UTC" "2014-06-28 UTC" "2014-06-30 UTC" "2014-07-12 UTC" "2014-07-29 UTC"
[11] "2014-07-29 UTC" "2014-08-12 UTC"

内部会调用guess_formats.

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