Hi Gabor,
I'm using this code but it doesn't work for me
> strptime2<-function (date,time) as.POSIXct(strptime(paste(date,time),
> "%m/%d/%Y %H:%M:%S"))
> dt=mapply(strptime2, "01/01/2008", "00:00:00", SIMPLIFY=FALSE,
> USE.NAMES=FALSE)
> df=data.frame(X1=dt,X2=1)
> dt
[[1]]
[1] "2008-01-01 Eastern Standard Time"
> df
structure.1199163600..class...c..POSIXt....POSIXct....tzone...... X2
1 2008-01-01 1
Here df looks very wrong to me.
So I tested this code:
> df2=data.frame(X1=as.POSIXct(Sys.time()),X2=1)
> df2
X1 X2
1 2008-02-17 23:43:08 1
> class(df2$X1)
[1] "POSIXt" "POSIXct"
Ah this worked as I expected.
So some tweaking here - SIMPLIFY is set TRUE now:
> strptime2<-function (date,time) as.POSIXct(strptime(paste(date,time),
> "%m/%d/%Y %H:%M:%S"))
> dt=mapply(strptime2, "01/01/2008", "00:00:00", SIMPLIFY=TRUE, USE.NAMES=FALSE)
> df=data.frame(X1=dt,X2=1)
> df
X1 X2
1 1199163600 1
> class(df$X1)
[1] "numeric"
Hmm... it worked, but not in a way I wanted. The class info is missing.
So how to get the result like this below? I do need that mapply +
strptime(paste), cos my CSV file is formatted in that way!
> df2
X1 X2
1 2008-02-17 23:43:08 1
> class(df2$X1)
[1] "POSIXt" "POSIXct"
Any insight?
Cheers,
Bo
> Date: Sun, 17 Feb 2008 15:53:28 -0500
> From: [EMAIL PROTECTED]
> To: [EMAIL PROTECTED]
> Subject: Re: [R] How to make a vector/list/array of POSIXlt object?
> CC: [email protected]
>
> Normally one uses POSIXct rather than POSIXlt for storage. See R News 4/1 for
> more info on date and time classes.
>
> On Feb 17, 2008 3:45 PM, Bo Zhou <[EMAIL PROTECTED]> wrote:
> >
> > Hi Guys,
> >
> > I'm cooking up my time series code. I want a data frame with first column
> > as timestamp in POSIXlt format.
> >
> > I hit on this the problem of how to create an array/list/vector of POSIXlt
> > objects. Code is as follows
> >
> >
> >
> > > dtt=array(dim = 2)
> > > t=as.POSIXlt( strptime("07/12/07 13:20:01", "%m/%d/%Y %H:%M:%S",tz="GMT"))
> > > dtt
> > [1] NA NA
> > > t
> > [1] "0007-07-12 13:20:01 GMT"
> > > dtt[1]=t
> > Warning message:
> > In dtt[1] = t :
> > number of items to replace is not a multiple of replacement length
> > > class(dtt)
> > [1] "list"
> > > class(t)
> > [1] "POSIXt" "POSIXlt"
> > > unclass(t)
> > $sec
> > [1] 1
> >
> > $min
> > [1] 20
> >
> > $hour
> > [1] 13
> >
> > $mday
> > [1] 12
> >
> > $mon
> > [1] 6
> >
> > $year
> > [1] -1893
> >
> > $wday
> > [1] 4
> >
> > $yday
> > [1] 192
> >
> > $isdst
> > [1] 0
> >
> > attr(,"tzone")
> > [1] "GMT"
> >
> >
> >
> > Seems like POSIXlt is matrix in this case.
> >
> > Any suggestions?
> >
> > Cheers,
> >
> > B
> > _________________________________________________________________
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> >
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