Date/time arithmetic

Date/time arithmetic is necessary to answer questions such as the following:

• How long did it take to complete an operation?
• What time will it be after 5 minutes?
• How many days are there until next month?

This recipe shows how you can answer these questions using the time package.

How to do it...

• To find out how much time has passed between two instances in time, use the Time.Sub method to subtract them.
• To find the duration from now to a later time, use time.Until(laterTime).
• To find how much time has passed since a given time, use time.Since(beforeTime).
• To find out what time it will be after a certain duration, use the Time.Add method. Use negative duration to find the time before a certain duration.
• To add/subtract years, months, or days to/from a time, use the Time.AddDate method.
• To compare two time.Time values, use the following:
  • Time.Equal to check whether two time values represent the same instance
  • Time...