[R] extracting months from a data

[KMNanus]

Thanks for this.  I wasn’t familiar with paste0, so I’ll call that and see if it works.

Ken
kmnanus at gmail.com
914-450-0816 (tel)
347-730-4813 (fax)



> On Mar 9, 2016, at 7:15 PM, 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 <mailto: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 <mailto: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 <mailto:kmnanus at gmail.com>
> >914-450-0816 (tel)
> >347-730-4813 (fax)
> >
> >
> >
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> 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 <mailto:ddalthorp at usgs.gov>
>