Convert a number to HH:MM:SS

Question

I have a number 154958. I want to convert to HH:MM:SS.

Answer I am looking is 15:49:58.

Answer 1

Convert to date then substring:

substr(strptime("154958", format = "%H%M%S"), 12, 20)

Or even better version (thanks @Roland):

format(strptime("154958", format = "%H%M%S"), format = "%H:%M:%S")