My data contains a variable "observation_date" and it contains values as:
1985-09-02 1985-09-15 1985-07-31 1985-09-02 I need to process data annually rather than daily, therefore I'm trying to 1) either extract the first 4 digits from this field and use them as a new variable "year" or 2) keep the variable as it is and process the analysis using the first 4 digits of the observation_date field. I'm not sure how to do either one of these approaches. I've looked in the R-archive help pages, date, strsplit and a few others > attach(gator) > observation_date[1:10] [1] 1985-09-02 1985-09-16 1985-07-31 1985-07-31 1985-09-02 1985-08-26 1985-07-31 1985-08-26 1985-09-02 1985-09-16 > as.date(observation_date) Error in as.date(observation_date) : Cannot coerce to date format > mode(observation_date) "numeric" > y <- as.character(observation_date) [1] "1985-09-02" "1985-09-16" "1985-07-31" "1985-07-31" "1985-09-02" "1985-08-26" "1985-07-31" "1985-08-26" "1985-09-02" "1985-09-16" < y.date <- as.date(y) [1] <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> <NA> on and on and on ... > x <- strsplit(observation_date, "-") Error in strsplit(observation_date, "-") : non-character argument All help is greatly appreciated. Thanks Steve Steve Friedman Ph. D. Spatial Statistical Analyst Everglades and Dry Tortugas National Park 950 N Krome Ave (3rd Floor) Homestead, Florida 33034 steve_fried...@nps.gov Office (305) 224 - 4282 Fax (305) 224 - 4147 ______________________________________________ R-help@r-project.org mailing list 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.
