如何解析这种日期格式?我应该将此冒号更改为点还是有人知道更好的解决方案?
> x <- "2012.01.15 09:00:02:002"
> strptime(x, "%Y.%m.%d %H:%M:%S:%OS")
[1] "2012-01-15 09:00:02"
> strptime(x, "%Y.%m.%d %H:%M:%OS")
[1] "2012-01-15 09:00:02"
> x <- "2012.01.15 09:00:02.002"
> strptime(x, "%Y.%m.%d %H:%M:%OS")
[1] "2012-01-15 09:00:02.001"