Marc;
Feature request:
Would it make sense to construct month.abb as a named vector so that the
operation that was attempted would have succeeded? Adding alphanumeric names
c("01", "02", "03", "04", "05", "06",
"07", "08", "09", "10", "11", "12") would allow character extraction from
substring or regex extracted month values which are always character-class.
Example:
> names(month.abb) <- c("01", "02", "03", "04", "05", "06",
+ "07", "08", "09", "10", "11", "12")
> month.abb
01 02 03 04 05 06 07 08 09 10 11 12
"Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"
> month.abb[ substr(Sys.Date(), 6,7) ]
09
"Sep"
--
David.
On Sep 23, 2014, at 9:03 AM, Marc Schwartz wrote:
> On Sep 23, 2014, at 10:41 AM, Kuma Raj <pollar...@gmail.com> wrote:
>
>> Dear R users,
>>
>> I have a data with month and year columns which are both characters
>> and wanted to create a new column like Jan-1999
>> with the following code. The result is all NA for the month part. What
>> is wrong with the and what is the right way to combine the two?
>>
>> ddf$MonthDay <- paste(month.abb[ddf$month], ddf$Year, sep="-" )
>>
>>
>> Thanks
>>
>>> dput(ddf)
>> structure(list(month = c("01", "02", "03", "04", "05", "06",
>> "07", "08", "09", "10", "11", "12"), Year = c("1999", "1999",
>> "1999", "1999", "1999", "1999", "1999", "1999", "1999", "1999",
>> "1999", "1999"), views = c(42, 49, 44, 38, 37, 35, 38, 39, 38,
>> 39, 38, 46), MonthDay = c("NA-1999", "NA-1999", "NA-1999", "NA-1999",
>> "NA-1999", "NA-1999", "NA-1999", "NA-1999", "NA-1999", "NA-1999",
>> "NA-1999", "NA-1999")), .Names = c("month", "Year", "views",
>> "MonthDay"), row.names = 109:120, class = "data.frame")
>>>
>>
>
>
>
> Since you are trying to use ddf$month as an index into month.abb, you will
> either need to coerce ddf$month to numeric in your code, or adjust how the
> data frame is created.
>
> In the case of the former approach:
>
>> paste(month.abb[as.numeric(ddf$month)], ddf$Year, sep="-" )
> [1] "Jan-1999" "Feb-1999" "Mar-1999" "Apr-1999" "May-1999" "Jun-1999"
> [7] "Jul-1999" "Aug-1999" "Sep-1999" "Oct-1999" "Nov-1999" "Dec-1999"
>
>
> Regards,
>
> Marc Schwartz
>
> ______________________________________________
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David Winsemius
Alameda, CA, USA
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