[R] SQL Changing Data Type

[Gabor Grothendieck]

On Fri, Jun 24, 2011 at 4:12 PM, GL <pflugg at shands.ufl.edu> wrote:
> Passing in two dates to a sql statement (sqldf). Is returning a factor. Tried
> setting back to a Date via as.Date, but get an error the error: character
> string is not in a standard unambiguous format. Any thoughts appreciated.
>
> Code/Results listed below:
>
>> summary(df.possible.combos)
>      Date                 Hour
>  Min.   :2011-03-01   Min.   : 0.00
>  1st Qu.:2011-03-23   1st Qu.: 5.75
>  Median :2011-04-14   Median :11.50
>  Mean   :2011-04-14   Mean   :11.50
>  3rd Qu.:2011-05-06   3rd Qu.:17.25
>  Max.   :2011-05-31   Max.   :23.00
>> summary(df.aggregate)
>      Date                 Hour           x
>  Min.   :2011-03-01   16     : 82   Min.   : 1.000
>  1st Qu.:2011-03-22   17     : 82   1st Qu.: 1.000
>  Median :2011-04-13   18     : 82   Median : 2.000
>  Mean   :2011-04-14   19     : 79   Mean   : 4.195
>  3rd Qu.:2011-05-07   20     : 76   3rd Qu.: 7.000
>  Max.   :2011-05-31   7      : 75   Max.   :20.000
>                      (Other):377
>> #merge raw data and all possible combinations
>>   df.final <- sqldf('select Date, Hour, x as RoomsInUse from
>> "df.aggregate"
> +     left join "df.possible.combos" using (Hour, Date)')
>> summary(df.final)
>      Date          Hour       RoomsInUse
>  15069.0: 16   16     : 82   Min.   : 1.000
>  15114.0: 16   17     : 82   1st Qu.: 1.000
>  15063.0: 15   18     : 82   Median : 2.000
>  15082.0: 15   19     : 79   Mean   : 4.195
>  15125.0: 15   20     : 76   3rd Qu.: 7.000
>  15044.0: 14   7      : 75   Max.   :20.000
>  (Other):762   (Other):377
>> thedate <- as.Date(df.final$Date)
> Error in charToDate(x) :
>  character string is not in a standard unambiguous format
>>

Please read the last line to every message to r-help and provide this
in reproducible form as requested.  Use dput to display all inputs and
showing all code. Also ensure you are using the latest version of
sqldf which is 0.4-1.

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