用zoo这个格式。
参考
> x.Date <- as.Date("2003-02-01") + c(1, 3, 7, 9, 14) - 1
> x.Date
[1] "2003-02-01" "2003-02-03" "2003-02-07" "2003-02-09" "2003-02-14"
> class(x.Date)
[1] "Date"
> x <- zoo(rnorm(5), x.Date)
> x
2003-02-01 2003-02-03 2003-02-07 2003-02-09 2003-02-14
0.01964254 0.03122887 0.64721059 1.47397924 1.29109889
> class(x)
[1] "zoo"
> plot(x)