Transform chr into date format for scale_x_date (ggplot2)
===

I'm trying to plot 'time of day' per week during 2000-2011. This is a follow-up to my earlier question [Aggregating mean “%H%M” in “week”][1] I would like to be able to use scale_x_date of ggplot2, but I'm having a hard time to transform my Group.1 *chr* which is %W/%g back to a Date format to be able to use this particular scale. I have tried a few different things, including the script below, but I don't end-up with what I am expecting...? 

    > out$Group.1<-as.Date(out$Group.1, "%W/%g")
    > out$Group.1
    [1] "2006-07-18" "2010-07-18" "2010-07-18" "2011-07-18" "2004-07-18" "2010-07-18"

Following Gsee's recommendations, this is my dataset:

    out <- aggregate(halibut_0A$stime, list(format(halibut_0A$datetime, "%W/%g")), mean)
    out[order(as.numeric(paste(substr(out[, 1], 4, 5), substr(out[, 1], 1, 2)))), ]
    > out
        Group.1                   x
    1     20/06 1970-01-01 04:26:00
    2     26/10 1970-01-01 03:21:00
    3     27/10 1970-01-01 08:30:45
    4     27/11 1970-01-01 09:12:40
    5     28/04 1970-01-01 09:40:00
    6     28/10 1970-01-01 09:03:24
    7     28/11 1970-01-01 06:52:40
    8     29/07 1970-01-01 06:07:15
    9     29/08 1970-01-01 05:36:00
    10    29/10 1970-01-01 08:13:16
    > str(out)
    'data.frame':	195 obs. of  2 variables:
     $ Group.1: chr  "20/06" "26/10" "27/10" "27/11" ...
     $ x      : POSIXct, format: "1970-01-01 04:26:00" "1970-01-01 03:21:00" ...

    #write now I can use geom_bar (discrete scale), but my out$Group.1, "%W/%g" is not in the chronological order...
        ggplot(out, aes(Group.1, x)) + geom_bar() +
          scale_y_datetime(labels = date_format("%H-%M"),breaks = date_breaks("1 hour")) + xlab("Week of the year and year")

  [1]: http://stackoverflow.com/questions/11524895/aggregating-mean-hm-in-week-bins-in-r