Formatting month abbreviations using as.Date
date, gsub, r
Solution
You are looking for `as.yearmon()` in the zoo package. Given your dates
dates <- c("Sep/2012","Aug/2012","Jul/2012")
we load the package and convert to the `"yearmon"` class
require(zoo)
dates1 <- as.yearmon(dates, format = "%b/%Y")
dates1
Which gives
R> dates1
[1] "Sep 2012" "Aug 2012" "Jul 2012"
You can coerce to an object of class `"Date"` using the `as.Date()` method
R> as.Date(dates1)
[1] "2012-09-01" "2012-08-01" "2012-07-01"
Which would be a simpler way of getting the thing you did via `gsub()`. There is a `frac` argument which controls how far through the month the day component should be:
R> as.Date(dates1, frac = 0.5)
[1] "2012-09-15" "2012-08-16" "2012-07-16"
But that may ont be sufficient for you.
If you really only want the dates stored as you have them, then they aren't really dates but if you are happy to work within the zoo package then the `"yearmon"` class can be used as an index for a `zoo` object which is a time series.
Problem
I'm working with monthly data and have a character vector of dates, formatted: ``` Sep/2012 Aug/2012 Jul/2012 ``` and so on, back to 1981. I've tried using ``` as.Date(dates, "%b/%Y") ``` where `%b` represents month abbreviations, but this only returns NAs. What am I doing wrong? Note: I already found a workaround using `gsub()` to add "01/" in front of each entry, like so: ``` 01/Sep/2012 01/Aug/2012 01/Jul/2012 ``` Then `as.Dates()` works, but this seems a little inelegant, and isn't strictly accurate anyway.