R中的每周时间序列

Question

I need to process five years of weekly data. I used the following command to create a time series from that:

my.ts <- ts(x[,3], start = c(2009,12), freq=52)

When plotting the series it looks good. However, the time points of the observations are stored as:

time(my.ts)
# Time Series:
# Start = c(2009, 12) 
# End = c(2014, 26) 
# Frequency = 52 
# [1] 2009.212 2009.231 2009.250 2009.269 2009.288 2009.308 2009.327 ...

I expected to see proper dates instead (which should be aligned with a Calendar). What shall I do?

Answer 1

That is how the "ts" class works.

The zoo package can represent time series with dates (and other indexes):

library(zoo)
z <- zooreg(1:3, start = as.Date("2009-12-01"), deltat = 7)

giving:

> z
2009-12-01 2009-12-08 2009-12-15 
         1          2          3 

> time(z)
[1] "2009-12-01" "2009-12-08" "2009-12-15"

The xts package and a number of other packages can also represent time series with dates although they do it by converting to POSIXct internally whereas zoo maintains the original class.