Q: R compare timestamps, which is earlier In R, I found a very strange behavior.
> x
[1] "2018-10-20 00:20:44 UTC"
> y
[1] "2018-10-20 02:14:59 CST"
> x < y
[1] FALSE

How could we make them correct?

A: What is CST here?  Did you mean America/Chicago?  
If I make that explicit, all is good:
R> library(anytime)
R> x <- utctime("2018-10-20 00:20:44 UTC", tz="UTC"); x
[1] "2018-10-20 00:20:44 UTC"
R> y <- anytime("2018-10-20 02:14:59 CST", tz="America/Chicago"); y
[1] "2018-10-20 02:14:59 CDT"
R> x < y
[1] TRUE
Warning message:
In check_tzones(e1, e2) : 'tzone' attributes are inconsistent
R> 

And helpfully we a warning about comparison across timezones.
