Converting hour, minutes columns in dataframe to time format

Question

I have a dataframe containing 3 columns including minutes and hours. I want to convert these columns (namely minutes and column) to time format. Given the data in drame:

Score Hour Min
10    10    56
23    17    01

I would like to get:

Score Time
10    10:56:00
23    17:01:00

Answer 1

You could use ISOdatetime to convert the numbers in the hour and min to a POSIXct object. However, a POSIXct object is only defined when it also includes a year, month and day. So depending on your needs to can do several things:

• If you need a real time object which is correctly printed in graphs for example and can be used in arithmetic (addition, subtraction), you need to use ISOdatetime. ISOdatetime returns a so called POSIXct object, which is an R object which represents time. Then in ISOdatetime you just use fixed values for year, month, and day. This ofcourse only works if your dataset does not span multiple years.
• If you just need a character column Time, you can convert the POSIXct output to string using strftime. By setting the format argument to "%H:%M:00". In this case however, you could also use sprintf to create the new character column without converting to POSIXct: sprintf("%s:%s:00", drame$Hour, drame$Min).