r - 时间戳记R序列毫秒

Question

我之前曾问过一个问题(请参阅:Sequence of Timestamps with Milliseconds)，但是由于某种原因，当我的时间从00:00:00开始时，我的代码无法正常工作。

我想从一个时间到另一个得到10hz时间的序列。但是这段代码给了我:

1   2018-06-01 00:00:00.000
2   2018-06-01 00:00:00.101
3   2018-06-01 00:00:00.202
4   2018-06-01 00:00:00.303
5   2018-06-01 00:00:00.404

当我需要时:

1   2018-06-01 00:00:00.000
2   2018-06-01 00:00:00.100
3   2018-06-01 00:00:00.200
4   2018-06-01 00:00:00.300
5   2018-06-01 00:00:00.400

代码:

options(digits.secs=3)
Time1 ="2018-06-01 00:00:00"
Time2 ="2018-06-01 00:00:10"
Time1 =as.POSIXct(Time1, format="%Y-%m-%d %H:%M:%OS", tz='UTC')
Time2 =as.POSIXct(Time2, format="%Y-%m-%d %H:%M:%OS", tz='UTC')
library(stringr)
dif_T2_T1 <- difftime(Time1, Time2, units = 'secs')
pattern <- '(\\d)+'
n <- as.numeric(str_extract(dif_T2_T1, pattern = pattern)) * 10
df_blank  <- data.frame(Timestamp = as.character(seq.POSIXt(Time1, Time2, units = 'seconds', length.out = n)))

Answer 1

由于对R中的毫秒数进行了四舍五入(请参见this post)，因此需要向向量添加一小部分分数。并且length.out应该是n+1，而不是n。

df_blank  <- data.frame(Timestamp = seq.POSIXt(Time1, Time2, length.out=n+1) + 0.0001)
head(df_blank)
#                Timestamp
#1 2018-06-01 00:00:00.000
#2 2018-06-01 00:00:00.100
#3 2018-06-01 00:00:00.200
#4 2018-06-01 00:00:00.300
#5 2018-06-01 00:00:00.400
#6 2018-06-01 00:00:00.500

如果不添加少量，您就可以看到问题所在。

df_blank  <- data.frame(Timestamp = seq.POSIXt(Time1, Time2, length.out=n+1))

head(format(df_blank, "%Y-%m-%d %H:%M:%OS6"))
#                   Timestamp
#1 2018-06-01 00:00:00.000000
#2 2018-06-01 00:00:00.099999
#3 2018-06-01 00:00:00.200000
#4 2018-06-01 00:00:00.299999
#5 2018-06-01 00:00:00.400000
#6 2018-06-01 00:00:00.500000

如果不进行格式化，您会看到一个非常奇怪的序列。

head(df_blank)
#              Timestamp
#1 2018-06-01 00:00:00.0
#2 2018-06-01 00:00:00.0
#3 2018-06-01 00:00:00.2
#4 2018-06-01 00:00:00.2
#5 2018-06-01 00:00:00.4
#6 2018-06-01 00:00:00.5