How do I use strptime or any other functions to parse time stamps with milliseconds in R?
time[1]
# [1] "2010-01-15 13:55:23.975"
strptime(time[1], format="%Y-%m-%d %H:%M:%S.%f")
# [1] NA
strptime(time[1], format="%Y-%m-%d %H:%M:%S")
# [1] "2010-01-15 13:55:23"`
Courtesy of the ?strptime help file (with the example changed to your value):
z <- strptime("2010-01-15 13:55:23.975", "%Y-%m-%d %H:%M:%OS")
z # prints without fractional seconds
op <- options(digits.secs=3)
z
options(op) #reset options
You can also use strptime(time[1], "%OSn") where 0 <= n <= 6, without having to set digits.secs.
来源：https://stackoverflow.com/questions/2150138/how-to-parse-milliseconds