I discovered that if I wanted control of the dates on the x axis I had to convert the IDate to as.POSIXct as well otherwise strange and undesirable things started happening - for instance all the dates were the same if I tried to format the dates in a particular way. So here is what I finished with my original data set.
qplot(data=ape.ph,x=as.POSIXct(date,tz="EST"), y=as.POSIXct(timei,tz="EST")) + scale_y_datetime(name="time",format="%H:%M") + scale_x_datetime(name="November",major="1 day", format = "%a %d") Farrel Buchinsky Google Voice Tel: (412) 567-7870 On Fri, Dec 16, 2011 at 10:35, Farrel Buchinsky <[email protected]> wrote: > Dear Matthew > > Thank you very much for your help. > I found something fascinating. I do not know the details of POSIXct and > iTime but look at this. > > library(data.table) > library(ggplot2) > > datetimes <- c("2011 NOV18 09:29:16", "2011 NOV18 10:42:40", "2011 NOV18 > 10:47:12", > "2011 NOV18 11:06:01", "2011 NOV18 11:35:34", "2011 NOV18 11:51:09", > "2011 NOV18 12:23:16", "2011 NOV18 12:30:01", "2011 NOV18 12:34:28", > "2011 NOV18 12:51:45", "2011 NOV18 12:56:37", "2011 NOV18 13:28:17", > "2011 NOV18 13:37:41", "2011 NOV18 13:49:07", "2011 NOV18 14:47:04", > "2011 NOV18 15:16:39", "2011 NOV18 15:17:10", "2011 NOV18 15:19:19", > "2011 NOV19 08:28:00", "2011 NOV19 09:20:55", "2011 NOV19 10:41:25", > "2011 NOV19 10:41:41", "2011 NOV19 12:53:15", "2011 NOV20 11:22:59", > "2011 NOV20 19:53:25", "2011 NOV21 07:16:35", "2011 NOV21 08:50:45", > "2011 NOV21 09:32:59", "2011 NOV21 09:43:01", "2011 NOV21 10:29:52", > "2011 NOV21 10:34:23", "2011 NOV21 10:37:09", "2011 NOV21 10:55:18", > "2011 NOV21 11:43:46", "2011 NOV21 11:46:50", "2011 NOV21 12:10:16", > "2011 NOV21 12:16:44", "2011 NOV21 13:53:42", "2011 NOV21 13:53:43", > "2011 NOV21 14:06:06", "2011 NOV21 14:23:39", "2011 NOV21 15:14:21", > "2011 NOV21 15:35:53", "2011 NOV21 15:46:29", "2011 NOV21 15:49:37", > "2011 NOV21 16:45:32", "2011 NOV21 20:36:31", "2011 NOV22 08:56:03", > "2011 NOV22 09:33:12", "2011 NOV22 09:39:52", "2011 NOV22 10:40:46", > "2011 NOV22 11:19:48", "2011 NOV22 11:23:32", "2011 NOV22 12:04:16", > "2011 NOV22 12:07:04", "2011 NOV22 12:23:31", "2011 NOV22 12:28:54", > "2011 NOV22 12:31:14", "2011 NOV22 12:53:31", "2011 NOV22 12:54:11", > "2011 NOV22 13:41:54", "2011 NOV22 15:34:11", "2011 NOV23 07:03:44", > "2011 NOV23 07:04:57", "2011 NOV23 08:01:42", "2011 NOV23 08:37:14", > "2011 NOV23 08:57:55", "2011 NOV23 09:00:34", "2011 NOV23 09:10:38", > "2011 NOV23 09:21:19", "2011 NOV23 09:23:58", "2011 NOV23 10:48:10", > "2011 NOV23 11:23:58", "2011 NOV23 11:49:14", "2011 NOV23 12:19:44", > "2011 NOV23 12:31:34", "2011 NOV23 12:48:00", "2011 NOV23 13:22:08", > "2011 NOV23 13:30:36", "2011 NOV23 14:01:56", "2011 NOV23 14:38:15", > "2011 NOV23 14:54:02", "2011 NOV23 15:33:31", "2011 NOV23 15:49:12", > "2011 NOV25 09:21:42", "2011 NOV25 09:22:25", "2011 NOV25 09:24:22", > "2011 NOV25 10:07:42", "2011 NOV25 15:03:15", "2011 NOV28 08:12:32", > "2011 NOV28 09:20:39", "2011 NOV28 09:26:09", "2011 NOV28 10:25:47", > "2011 NOV28 11:19:40", "2011 NOV28 11:54:54", "2011 NOV28 14:33:53", > "2011 NOV28 15:08:25", "2011 NOV28 15:09:25", "2011 NOV28 15:23:07", > "2011 NOV28 15:23:30", "2011 NOV28 15:50:35", "2011 NOV29 08:22:39", > "2011 NOV29 09:08:51", "2011 NOV29 09:10:15", "2011 NOV29 10:44:17", > "2011 NOV29 11:32:05", "2011 NOV29 12:00:52", "2011 NOV29 12:32:48", > "2011 NOV29 13:21:50", "2011 NOV29 13:22:12", "2011 NOV29 13:22:38", > "2011 NOV29 13:23:35", "2011 NOV29 13:28:38", "2011 NOV29 13:29:44", > "2011 NOV29 13:30:25", "2011 NOV29 13:32:13", "2011 NOV29 13:33:28", > "2011 NOV29 13:35:59", "2011 NOV29 13:37:01", "2011 NOV29 13:39:37", > "2011 NOV29 13:41:33", "2011 NOV29 14:08:07", "2011 NOV29 14:09:53", > "2011 NOV29 14:13:15", "2011 NOV29 14:16:16", "2011 NOV29 14:17:32", > "2011 NOV29 14:37:05", "2011 NOV29 14:59:51", "2011 NOV29 14:59:51", > "2011 NOV29 14:59:54", "2011 NOV29 15:00:10", "2011 NOV29 15:13:22", > "2011 NOV29 16:09:50", "2011 NOV29 16:10:17", "2011 NOV29 16:31:14", > "2011 NOV29 16:43:20", "2011 NOV30 09:22:09", "2011 NOV30 10:19:21", > "2011 NOV30 11:42:04", "2011 NOV30 11:50:11", "2011 NOV30 12:21:11", > "2011 NOV30 13:06:39") > > datetimes <- strptime(datetimes,"%Y %b%d %H:%M:%S") > dtdt <- IDateTime(datetimes) > setkey(x=dtdt,idate,itime) > plot(dtdt$idate,dtdt$itime)#works although I still need to figure out how > to get times that I, as a human, understand > qplot(x=dtdt$idate,y=dtdt$itime) # gives an error > > #Error in as.data.frame.default(x[[i]], optional = TRUE) : > # cannot coerce class '"ITime"' into a data.frame > > dtdt[,qplot(idate,itime)]#same error > > > qplot(x=dtdt$idate,y=as.POSIXct(dtdt$itime,tz="EST")) #have to specify the > time zone otherwise I got evertying at UTC > > *Clearly this has something to do with the way ggplot wants its data. > Plot handled it but qplot did not.* > > > Farrel Buchinsky[?] > > > > > On Fri, Dec 16, 2011 at 03:50, Matthew Dowle <[email protected]>wrote: > >> Hi. >> >> You should be able to add more than one column in one step using := by >> setting with=FALSE like this : >> >> > DT = data.table(a=1:3,b=4:6) >> > DT >> a b >> [1,] 1 4 >> [2,] 2 5 >> [3,] 3 6 >> > DT[,c("newcol1","newcol2"):=list(7:9,3.14)] >> Error in `[.data.table`(DT, , `:=`(c("newcol1", "newcol2"), >> list(7:9, : >> LHS of := must be a single column name, when with=TRUE. When >> with=FALSE the LHS may be a vector of column names or positions. >> >> so set with=FALSE : >> >> > DT[,c("newcol1","newcol2"):=list(7:9,3.14),with=FALSE] >> Error in `[.data.table`(DT, , `:=`(c("newcol1", "newcol2"), >> list(7:9, : >> Logical error. Can only add new columns one at a time currently >> > >> >> I intended that to work so I'll take a look. But, the intention is at >> some point to enable this : >> >> DT[,{ newcol1 := .... >> newcol2 := .... >> newcol3 := newcol1 + newcol2 >> }, by=... ] >> >> where not only can you add multiple columns by reference and by group, >> but they can 'see' previous columns just added. That's going to be quite >> tricky to implement so don't hold your breath! >> >> In the meantime it's either one at a time with :=, or use (slower) [<- >> method to add multiple columns (via at least one full table copy). >> >> Re plotting, I'm hoping to learn ggplot2 myself soon, so bear that in >> mind, but this is the way I thought should work : >> >> ape.ph[,qplot(date, timei)] >> >> If that gives the same error I'm not sure why it would try to coerce >> ITime into a data.frame. Does anyone else know? If you can provide some >> example data it might help save us time to reproduce it. >> >> Matthew >> >> >> >> On Thu, 2011-12-15 at 19:25 -0500, Farrel Buchinsky wrote: >> > I was able to take a column of dates and times that looked like this >> > >> > 2011 NOV18 09:29:16 >> > >> > >> > I then tried this >> > >> > ape.ph[,date:=IDateTime(strptime(ape.ph$time,"%Y %b%d %H:%M:%S"))[[1]]] >> > ape.ph[,timei:=as.ITime(strptime(ape.ph$time,"%Y %b%d %H:%M:%S"))] >> > >> > >> > I had to create one column called date to accept the first column of >> > the IDateTime output. There does not appear to be a way to use the >> > IDateTime function and take both of its columns and stick it into the >> > data.table since one can only add one new column at a time as far as I >> > can tell. Anyway, I then created a variable timei to accept the time. >> > >> > >> > I wanted to plot the times that something happened on the y axis and >> > then on the x axis I wanted to have the various dates >> > >> > >> > library(ggplot2) >> > qplot(ape.ph[,date], ape.ph[,timei]) >> > >> > >> > but alas I got this >> > >> > >> > Error in as.data.frame.default(x[[i]], optional = TRUE) : >> > cannot coerce class '"ITime"' into a data.frame >> > >> > >> > I am eventually hoping for this >> > qplot(ape.ph[,date], ape.ph[,timei]) + >> > scale_y_datetime(format="%H:%M:%S") + >> > xlab("Day") + ylab("Hour") >> > >> > >> > Do you have any examples of dates and times used in a data.table and >> > then being used to plot graphs? I would love to see some examples. I >> > could not find any >> > >> > >> > >> > >> > Farrel Buchinsky >> > Google Voice Tel: (412) 567-7870 >> > >> > >> > _______________________________________________ >> > datatable-help mailing list >> > [email protected] >> > >> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help >> >> >> >
<<517.gif>>
_______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
