我需要将日期格式从“xx 时间前”更改为：一年前，1 周前为“%Y/%m/%d”答案

【问题标题】：I need to change date format from "xx time ago" like: a year ago, 1 week ago to "%Y/%m/%d"我需要将日期格式从“xx 时间前”更改为：一年前，1 周前为“%Y/%m/%d”
【发布时间】：2023-03-18 03:18:01
【问题描述】：

我有从互联网收集的数据。日期列格式类似于“1 个月前”“2 年前”“4 天前”，我需要更改此格式。

我试过了：

googleR$`Date/Time` <- as.Date.character(googleR$`Date/Time`, 
                                         format = format(googleR$`Date/Time`), 
                                         tryFormats = c("%d/%m/%Y"))

但它只给了我所有记录的今天日期

我也尝试了很多其他方法，但出现了同样的错误

“字符串不是标准的明确格式”

这是我要转换的数据：

format.factor(googleR$`Date/Time`)
 [1] "7 months ago " "2 months ago " "a week ago   " "2 years ago  " "2 years ago  " "5 months ago " "10 months ago"
 [8] "2 years ago  " "4 years ago  " "2 years ago  " "2 years ago  " "11 months ago" "3 years ago  " "3 years ago  "
[15] "2 years ago  " "2 years ago  " "10 months ago" "10 months ago" "a year ago   " "a year ago   " "2 years ago  "
[22] "2 years ago  " "2 years ago  " "2 years ago  " "2 years ago  " "2 years ago  " "3 years ago  " "4 years ago  "
[29] "4 years ago  " "a week ago   " "a week ago   " "2 weeks ago  " "a month ago  " "2 months ago " "5 months ago "
[36] "7 months ago " "7 months ago " "8 months ago " "10 months ago" "10 months ago" "a year ago   " "a year ago   "
[43] "a year ago   " "a year ago   " "a year ago   " "a year ago   " "a year ago   " "2 years ago  " "2 years ago  "
[50] "2 years ago  " "4 years ago  " "6 years ago  "

【问题讨论】：

标签： r date

【解决方案1】：

您可以使用sub从每个元素中删除“之前”，然后使用lubridate的add_with_rollback如下

library(lubridate)
add_with_rollback(Sys.time(), - as.period(sub("\\s+ago", "", x)))

结果

"2019-02-28 18:13:18 CET"  "2017-03-31 18:13:18 CEST" "2019-03-27 18:13:18 CET"

数据

x <- c("1 month ago", "2 years ago", "4 days ago")

【讨论】：

不错！我什至不知道“add_with_rollback”！

【解决方案2】：

您可能需要首先使用正则表达式来确定您拥有的时间间隔类型，然后从那里开始。我喜欢 stringr 包。例如，如果 IN 是你的输入字符串，OUT 是你想要的输出，你可以说

 if(str_detect(IN, "day")){OUT <- as.numeric(str_extract(IN, "^[0-9]*"))}

现在，你得到了天数，你可以做类似的事情

 Sys.Date() - OUT

获取日期。然后你可以在几个月和几年内做基本相同的事情。这不可避免地会是近似的，因为并非所有月份都有相同的天数，但听起来你的输入数据无论如何都不是超级精确的。

【讨论】：