[R] extracting months from a data

[Jeff Newmiller]

Still not recommended.  That takes more steps, is harder to understand, and will break when given "29-Feb" as input. 
-- 
Sent from my phone. Please excuse my brevity.

On March 9, 2016 4:15:31 PM PST, "Dalthorp, Daniel" <ddalthorp at usgs.gov> wrote:
>Or:
>
>x <- c( "3-Oct", "10-Nov" )
>format(as.Date(paste0(x,rep("-1970",length(x))),format='%d-%b-%Y'),'%b')
>
># the 'paste0' appends a year to the text vector
># the 'as.Date' interprets the strings as dates with format 
>10-Jun-2016
>(e.g.)
># the 'format' returns a string with date in format '%b' (which is just
>the
>name of the month)
>
>On Wed, Mar 9, 2016 at 3:52 PM, Jeff Newmiller
><jdnewmil at dcn.davis.ca.us>
>wrote:
>
>> Your dates are incomplete (no year) so I suggest staying away from
>the
>> date functions for this. Read ?regex and ?sub.
>>
>> x <- c( "3-Oct", "10-Nov" )
>> m <- sub( "^\\d+-([A-Za-z]{3})$", "\\1", x )
>>
>> --
>> Sent from my phone. Please excuse my brevity.
>>
>> On March 9, 2016 10:14:25 AM PST, KMNanus <kmnanus at gmail.com> wrote:
>> >I have a series of dates in  format 3-Oct, 10-Oct, 20-Oct, etc.
>> >
>> >I want to create a variable of just the month.  If I convert the
>date
>> >to a character string, substr is ineffective because some of the
>dates
>> >have 5 characters (3-Oct) and some have 6 (10-Oct).
>> >
>> >Is there a date function that accomplishes this easily?
>> >
>> >Ken
>> >kmnanus at gmail.com
>> >914-450-0816 (tel)
>> >347-730-4813 (fax)
>> >
>> >
>> >
>> >______________________________________________
>> >R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> >https://stat.ethz.ch/mailman/listinfo/r-help
>> >PLEASE do read the posting guide
>> >http://www.R-project.org/posting-guide.html
>> >and provide commented, minimal, self-contained, reproducible code.
>>
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>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
>
>-- 
>Dan Dalthorp, PhD
>USGS Forest and Rangeland Ecosystem Science Center
>Forest Sciences Lab, Rm 189
>3200 SW Jefferson Way
>Corvallis, OR 97331
>ph: 541-750-0953
>ddalthorp at usgs.gov

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