我想减去 POSIXct。我可以做到这一点,但根据第一行(我猜?),差异将以秒或分钟为单位。下面您可以看到第一个差异以秒为单位,第二个差异以分钟为单位,因为我更改了第一行中的时间差:
#diff in seconds because 1st row time diff is small?
t1<- as.POSIXct(c("2015-02-02 20:18:03 00:00:00", "2015-02-02 20:17:02 00:00:00"),"GMT")
t2<- as.POSIXct(c("2015-02-02 20:18:02 00:00:00","2015-02-02 20:18:02 00:00:00"),"GMT")
d<-data.frame(t1= t1, t2= t2)
d$t1-d$t2
#diff in seconds because 1st row time diff is larger?
t1<- as.POSIXct(c("2015-02-02 20:13:03 00:00:00", "2015-02-02 20:17:02 00:00:00"),"GMT")
t2<- as.POSIXct(c("2015-02-02 20:18:02 00:00:00","2015-02-02 20:18:02 00:00:00"),"GMT")
d<-data.frame(t1= t1, t2= t2)
d$t1-d$t2
results:
> #diff in seconds because 1st row time diff is small?
> t1<- as.POSIXct(c("2015-02-02 20:18:03 00:00:00", "2015-02-02 20:17:02 00:00:00"),"GMT")
> t2<- as.POSIXct(c("2015-02-02 20:18:02 00:00:00","2015-02-02 20:18:02 00:00:00"),"GMT")
> d<-data.frame(t1= t1, t2= t2)
> d$t1-d$t2
Time differences in secs
[1] 1 -60
>
>
> #diff in seconds because 1st row time diff is larger?
> t1<- as.POSIXct(c("2015-02-02 20:13:03 00:00:00", "2015-02-02 20:17:02 00:00:00"),"GMT")
> t2<- as.POSIXct(c("2015-02-02 20:18:02 00:00:00","2015-02-02 20:18:02 00:00:00"),"GMT")
> d<-data.frame(t1= t1, t2= t2)
> d$t1-d$t2
Time differences in mins
[1] -4.983333 -1.000000
我希望差异始终以秒为单位,无论第一行差异是什么。有办法实现这一点吗?
谢谢。