Concatenating Dates into a single Column - r

Question

My dates in Submitted.on column are of different formats hence resorted to converting the various formats separately and then concatenating them into a new column using ifelse and as.Date. But the however when I use strptime to have the timestamp also in the new column it throws error and a warning message.
data$Submitted.on[0:5]
#[1] 02-06-02 0:00 03/30/2010 23:15:12
#[3] 11-05-09 6:28 07/29/2009 23:07:38
#[5] 07-10-05 0:00
vec1 = as.character(strptime(data$Submitted.on, "%m/%d/%Y %H:%M:%S"))
vec1[0:5]
#[1] NA "2010-03-30 23:15:12"
#[3] NA "2009-07-29 23:07:38"
#[5] NA
vec2 = as.character(strptime(data$Submitted.on, "%m-%d-%y %H:%M"))
vec2[0:5]
#[1] "2002-02-06 00:00:00" NA
#[3] "2009-11-05 06:28:00" NA
#[5] "2005-07-10 00:00:00"
data['new_format']=as.Date(ifelse(is.na(vec1),vec2,vec1))
data[0:5,'new_format']
#[1] "2002-02-06" "2010-03-30" "2009-11-05" "2009-07-29"
#[5] "2005-07-10"
Using as.Date works great but when I use strptime for timestamp also , it gives warning message.
data['new_format']=strptime(ifelse(is.na(vec1),vec2,vec1),"%Y-%m-%d
%H:%M:%S")
#Warning message:
#In `[<-.data.frame`(`*tmp*`, "new_format", value = list(sec = c(0, :
#provided 11 variables to replace 1 variables
data[0:5,'new_format']
[1] 0 12 0 38 0
Any help on how to have the timestamp also will be of great help.

Answer 1

We can use parse_date_time from lubridate
library(lubridate)
parse_date_time(data$Submitted.on, guess_formats(data$Submitted.on,
c("mdy HMS", "mdy MS")))
#[1] "2002-02-06 00:00:00 UTC" "2010-03-30 23:15:12 UTC" "2009-11-05 00:06:28 UTC"
#[4] "2009-07-29 23:07:38 UTC" "2005-07-10 00:00:00 UTC"
Regarding the use of ifelse, we would advocate against this as strptime gives a POSIXlt class. So, instead of ifelse, one can use the indexing method
v1 <- strptime(data$Submitted.on, "%m/%d/%Y %H:%M:%S", tz = "UTC")
v1[is.na(v1)] <- strptime(data$Submitted.on[is.na(v1)], "%m-%d-%y %H:%M", tz = "UTC")
v1
#[1] "2002-02-06 00:00:00 UTC" "2010-03-30 23:15:12 UTC" "2009-11-05 06:28:00 UTC"
#[4] "2009-07-29 23:07:38 UTC" "2005-07-10 00:00:00 UTC"
data
data <- structure(list(Submitted.on = c("02-06-02 0:00", "03/30/2010 23:15:12",
"11-05-09 6:28", "07/29/2009 23:07:38", "07-10-05 0:00")),
.Names = "Submitted.on", row.names = c(NA, -5L), class = "data.frame")