r - Convert date-time string to class Date

Question

I have a data frame with a character column of date-times.

When I use as.Date, most of my strings are parsed correctly, except for a few instances. The example below will hopefully show you what is going on.

# my attempt to parse the string to Date -- uses the stringr package
prods.all$Date2 <- as.Date(str_sub(prods.all$Date, 1, 
                str_locate(prods.all$Date, " ")[1]-1), 
                "%m/%d/%Y")

# grab two rows to highlight my issue
temp <- prods.all[c(1925:1926), c(1,8)]
temp
#                    Date      Date2
# 1925  10/9/2009 0:00:00 2009-10-09
# 1926 10/15/2009 0:00:00 0200-10-15

As you can see, the year of some of the dates is inaccurate. The pattern seems to occur when the day is double digit.

Any help you can provide will be greatly appreciated.

question from:https://stackoverflow.com/questions/4310326/convert-date-time-string-to-class-date

Answer 1

The easiest way is to use lubridate:

library(lubridate)
prods.all$Date2 <- mdy(prods.all$Date2)

This function automatically returns objects of class POSIXct and will work with either factors or characters.