Reading time data of different lengths and making them the same in R

Question

I am reading in some time data from a text file into R. The data is in column N.Time . Some of the data in N.Time has hours, minutes, and seconds (for example 1:45:02). Instances that are under an hour just have minutes and seconds (for example 34:25)

The data is read in as characters. I want to convert to times to perform calculations later. However the formatting is messing me up. If I use the %H:%M:%S format, all of the instances that don't have hours are converted to NA. If I use the %M:%S format, the instances that have hours get messed up (for example 1:45:02 becomes 00:01:05).

Any advice on how to get these two formats to work together? Ideally somehow just add 00: in the hours slot to all instances that don't have hours?

Answer 1

If all the times have the same fixed format apart from the missing hours issue, then the regex to fill in the hours with 00: isn't too complicated:

> times = c("1:45:02", "34:25")
> gsub("^(\\d\\d:\\d\\d)$", "00:\\1", times, perl = TRUE)
[1] "1:45:02"  "00:34:25"