[R] Date variable error

[Kurt_Helf at nps.gov]

Greetings
     In attempting to create a date variable based on month (e.g.,
February, April, etc.) and year (e.g., 2006) data, wherein I converted
Month to a factor with Jan=1...Dec=12, I used the following command:

data$Date<-mdy.date(month=data$Month,day=15,year=data$Year)

however, I get a message "Error: trunc not meaningful for factors"
Any advice?
Cheers
Kurt

***************************************************************
Kurt Lewis Helf, Ph.D.
Ecologist
EEO Counselor
National Park Service
Cumberland Piedmont Network
P.O. Box 8
Mammoth Cave, KY 42259
Ph: 270-758-2163
Lab: 270-758-2151
Fax: 270-758-2609
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