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Exercise

Create and format times

Similar to working with dates, you can use as.POSIXct() to convert from a character string to a POSIXct object, and format() to convert from a POSIXct object to a character string. Again, you have a wide variety of symbols:

  • %H: hours as a decimal number (00-23)
  • %I: hours as a decimal number (01-12)
  • %M: minutes as a decimal number
  • %S: seconds as a decimal number
  • %T: shorthand notation for the typical format %H:%M:%S
  • %p: AM/PM indicator

For a full list of conversion symbols, consult the strptime documentation in the console:

?strptime

Again,as.POSIXct() uses a default format to match character strings. In this case, it's %Y-%m-%d %H:%M:%S. In this exercise, abstraction is made of different time zones.

Instructions
100 XP
  • Convert two strings that represent timestamps, str1 and str2, to POSIXct objects called time1 and time2.
  • Using format(), create a string from time1 containing only the minutes.
  • From time2, extract the hours and minutes as "hours:minutes AM/PM". Refer to the assignment text above to find the correct conversion symbols!
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