如何将日期时间格式“%Y-%m-%d %H:%M:%S”转换为 r 数据帧中的“%Y-%m-%d %H:%M:%S.sss” ？第二个分数

Question

我很难在 R data.frame 中将日期时间格式 "%Y-%m-%d %H:%M:%S" 转换为 "%Y-%m-%d %H:%M:%S.sss"？请注意，我想要带小数秒的秒数。

Answer 1

我不太确定你在问什么。您可以使用例如格式化小数秒"%OS3".

来自?strptime

Specific to R is ‘%OSn’, which for output gives the seconds truncated to ‘0 <= n <= 6’ decimal places (and if ‘%OS’ is not followed by a digit, it uses the setting of ‘getOption("digits.secs")’, or if that is unset, ‘n = 0’). Further, for ‘strptime’ ‘%OS’ will input seconds including fractional seconds. Note that ‘%S’ does not read fractional parts on output.

示例：

ss <- "2018-08-22 21:30:00.5"
format(as.POSIXct(ss, format = "%Y-%m-%d %H:%M:%OS"), format = "%Y-%m-%d %H:%M:%OS3")
#[1] "2018-08-22 21:30:00.500"

或示例 data.frame

df <- data.frame(
    date = c("2018-08-22 21:30:00", "2018-08-22 22:00:00", "2018-08-22 22:30:00"))
transform(df, new.date = format(
    as.POSIXct(date, format = "%Y-%m-%d %H:%M:%OS"), 
    format = "%Y-%m-%d %H:%M:%OS3"))
#    date                new.date
#1 2018-08-22 21:30:00 2018-08-22 21:30:00.000
#2 2018-08-22 22:00:00 2018-08-22 22:00:00.000
#3 2018-08-22 22:30:00 2018-08-22 22:30:00.000

如何将日期时间格式“%Y-%m-%d %H:%M:%S”转换为 r 数据帧中的“%Y-%m-%d %H:%M:%S.sss” ？第二个分数

how to convert date time format "%Y-%m-%d %H:%M:%S" to "%Y-%m-%d %H:%M:%S.sss" in r dataframe? second with fraction

r

timestamp

strptime