[R] Date as Integer

[William Dunlap]

It would help if you supplied a small dataset so we could
reproduce your problem problem.  Here is one that gives the same
error.  (I also moved some parentheses around so "%y-%m-%d"
is an argument to as.Date() instead of to group_by().)
  data.frame(pickdate=paste(sep="-",15,08,c(21,22,21,22,22)),
waybill=2^(0:4)) %>%
    group_by(as.Date(pickdate,"%y-%m-%d")) %>%
    summarize(Total=count(waybill))
  #Error: no applicable method for 'group_by_' applied to an object of
class "c('double', 'numeric')"

I think count() is a wrapper for summarize() (or summarise() outside the
US),
not something to call from within summarize(), but I may be wrong (the help
file is terse).  Try using n() instead:
  data.frame(pickdate=paste(sep="-",15,08,c(21,22,21,22,22)),
waybill=2^(0:4)) %>%
    group_by(as.Date(pickdate,"%y-%m-%d")) %>%
    summarize(N=n(), Sum=sum(waybill), Mean=mean(waybill))
  #Source: local data frame [2 x 4]
  #
  #  as.Date(pickdate, "%y-%m-%d") N Sum     Mean
  #1                    2015-08-21 2   5 2.500000
  #2                    2015-08-22 3  26 8.666667




Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Sat, Aug 22, 2015 at 12:43 AM, Shivi82 <shivibhatia at ymail.com> wrote:

> Hi All,
>
> I am using dplyr package and need to find total bills booked grouped on a
> date level however my date is integer.
> In the code below i was trying to change date format from integer. However
> it is throwing an error:
>
> "no applicable method for 'group_by_' applied to an object of class
> "c('integer', 'numeric')"
>
> ak%>%
>   group_by(as.Date(pickdate),"%y%m%d")%>%
>   summarise(Total=count(waybill))
>
> Do i need to create a new var first changing the date and then group it or
> as.Date will work as i added in dplyr.
>
>
>
>
>
> --
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> Sent from the R help mailing list archive at Nabble.com.
>
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