[R] Converting a dataframe column from string to datetime

[jim holtman]

I think you want to use as.POSIXct to get the date value:

> v<-c("Fri Feb 05 20:00:01.43000 2010","Fri Feb 05 20:00:02.274000 2010","Fri Feb 05 20:00:02.274000 2010","Fri Feb 05 20:00:06.34000 2010")
> x <- as.POSIXct(v, format= "%a %b %d %H:%M:%OS %Y")
> x
[1] "2010-02-05 20:00:01 EST" "2010-02-05 20:00:02 EST"
[3] "2010-02-05 20:00:02 EST" "2010-02-05 20:00:06 EST"
> str(x)
 POSIXct[1:4], format: "2010-02-05 20:00:01" "2010-02-05 20:00:02" ...


On Fri, Oct 1, 2010 at 1:59 AM, rajeshj at cse.iitm.ac.in
<rajeshj at cse.iitm.ac.in> wrote:
>
> Hi,
>
> I have a dataframe column of the form
> v<-c("Fri Feb 05 20:00:01.43000 2010","Fri Feb 05 20:00:02.274000 2010","Fri Feb 05 20:00:02.274000 2010","Fri Feb 05 20:00:06.34000 2010")
>
> I need to convert this to datetime form. I did the following..
>
> lapply(v,function(x){strptime(x, "%a %b %d %H:%M:%OS %Y")})
>
> This gives me a list that looks like this...
>
> [[1]]
> [1] "2010-02-05 20:00:01.43"
> [[2]]
> [1] "2010-02-05 20:00:02.274"
> [[3]]
> [1] "2010-02-05 20:00:02.274"
> [[4]]
> [1] "2010-02-05 20:00:06.34"
>
> However, when I do an unlist...I gets converted to something like this...
>
> sec      min    hour    mday     mon    year    wday    yday   isdst     sec     min    hour    mday     mon    year    wday    yday   isdst     sec
>  1.430   0.000  20.000   5.000   1.000 110.000   5.000  35.000   0.000   2.274   0.000  20.000   5.000   1.000 110.000   5.000  35.000   0.000   2.274
>    min    hour    mday  mon    year    wday    yday   isdst     sec     min    hour    mday     mon    year    wday    yday   isdst
>  0.000  20.000   5.000   1.000 110.000   5.000  35.000   0.000   6.340   0.000  20.000   5.000   1.000 110.000   5.000
>
> I want it to become a dataframe column except for a change in the datatype to datetime...how can I achieve this?
>        [[alternative HTML version deleted]]
>
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-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?