Htykuut

I am writing a function where I plot several different data frames composed by time series.
The data frames are composed by several columns. The first one of each is always "time", and the following are the parameters.
Any data frame is different from each other

Once I imported the data set, the function create a calendar vector "Time"

Time <- as.POSIXct(TS[,1])

In a for loop, I use the function xts() to create the time series of one single parameter (one by one), using the column "time" to order the time series.

xts(TS[,i],order.by = Time)

then I plot.

As result, the script looks like this

TS <- read.table("ts.txt",header = T, dec = ".")

Time <- as.POSIXct(TS[,1])



    for (i in 2:length(TS[1,])

    {

    p <- plot(xts(TS[,i],order.by = Time)

    print(p)

    }

I have problems with as.POSIXct() when the format of my vector time in the data frames is not yyyy-mm-dd. Here few examples:

In some data frames, in "time" I have only "yyyy" in which pasting the "mm-dd" to "yyyy", would not make any sense because of the data (the columns, in this case, are the months).

In other situations, I have also negative dates because they are BC.

Are there other functions I can use to create calendar dates suitable to xts() using a different format like mine?

Here three examples of data set I have the problem with:

#1

year <- c(seq(1900, 2000, by = 10))

Jan <- c(rnorm(length(year), mean = 1, 5))

Feb <- c(rnorm(length(year), mean = 6, 9))

TS <- as.data.frame(cbind(year,Jan,Feb))                    

str(TS)



#2

year <- c(seq(-500, 2000, by = 100))

Jan <- c(rnorm(length(year), mean = 1, 5))

Feb <- c(rnorm(length(year), mean = 6, 9))

TS <- as.data.frame(cbind(year,Jan,Feb))                    

str(TS)



#3

time <- c("-100/01/01", "-100/06/01", "0/01/01", "1400/01/01", "2000/01/01")

people <- abs(c(rnorm(length(time), mean = 6, 9)))

TS <- as.data.frame(cbind(time,people))

str(TS)