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time-interval.md

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Time Interval

A time interval is the intervening time between two time points. Source: Wikipedia ISO8601

This library implements the Time Interval type via ISO8601::TimeInterval with the following constructors:

  • TimeInterval.new(String) (or TimeInterval.parse(String))
  • TimeInterval.from_duration(Duration, Hash<DateTime>)
  • TimeInterval.from_datetime(DateTime, DateTime)

Supported patterns

<start>/<end>
<start>/<duration>
<duration>/<end>

Where <start> and <end> are points in time and <duration> is an amount of time.

The pattern <duration> is not implemented; instead, you can use TimeInterval.from_duration.

Usage

<start>/<end>

The resulting time interval will have a starting point based on the provided <start> pattern and an ending point based on the provided <end> pattern.

ti = ISO8601::TimeInterval.parse('2015-12-12T19:53:00Z/2015-12-13T19:53:00Z')
ti.start_time.to_s  # => '2015-12-12T19:53:00Z'
ti.end_time.to_s    # => '2015-12-13T19:53:00Z'
ti.size             # => 86_400.0

<start>/<duration>

The resulting time interval will have a starting point based on the provided <start> pattern and an ending point result of <start> + <duration>.

ti = ISO8601::TimeInterval.parse('2015-12-12T19:53:00Z/P1D')
ti.start_time.to_s  # => '2015-12-12T19:53:00Z'
ti.end_time.to_s    # => '2015-12-13T19:53:00Z'
ti.size             # => 86_400.0

<duration>/<end>

The resulting time interval will have a starting point result of <end> - <duration> and an ending point based on the provided <end> pattern.

ti = ISO8601::TimeInterval.parse('P1D/2015-12-13T19:53:00Z')
ti.start_time.to_s  # => '2015-12-12T19:53:00Z'
ti.end_time.to_s    # => '2015-12-13T19:53:00Z'
ti.size             # => 86_400.0

TimeInterval.from_duration

duration = ISO8601::Duration.new('P1D`)
start_time = ISO8601::DateTime.new('2015-12-12T19:53:00Z')
ti = ISO8601::TimeInterval.from_duration(start_time, duration)
ti.start_time.to_s  # => '2015-12-12T19:53:00Z'
ti.end_time.to_s    # => '2015-12-13T19:53:00Z'
ti.size             # => 86_400.0


end_time = ISO8601::DateTime.new('2015-12-13T19:53:00Z')
ti2 = ISO8601::TimeInterval.from_duration(duration, end_time)
ti2.start_time.to_s  # => '2015-12-12T19:53:00Z'
ti2.end_time.to_s    # => '2015-12-13T19:53:00Z'
ti2.size             # => 86_400.0

TimeInterval.from_datetime

This constructor is an alternative way to <start>/<end> via Ruby objects.

start_time = ISO8601::DateTime.new('2015-12-12T19:53:00Z')
end_time = ISO8601::DateTime.new('2015-12-13T19:53:00Z')
ti2 = ISO8601::TimeInterval.from_duration(start_time, end_time)
ti2.start_time.to_s  # => '2015-12-12T19:53:00Z'
ti2.end_time.to_s    # => '2015-12-13T19:53:00Z'
ti2.size             # => 86_400.0

Operate with time intervals

TimeInterval is Comparable, so you can use the usual <, >, <=, >=, == to compare against another TimeInterval. Is equivalent to get the amount of seconds via #to_f and compare the resulting numbers.

A time interval can be viewed as an ordered set of datetime elements:

  • #empty? checks if an interval is empty.
  • #include? checks if a DateTime is part of the time interval.
  • #intersect? checks if two time intervals overlap.
  • #intersection returns the intersected time interval if the two intervals intersect.
  • #disjoint? checks if two time intervals don't intersect.
  • #subset? checks if a time interval is included in another one.
  • #superset? checks if a time interval is included in another one.
  • #first is the lower bound.
  • #last is the upper bound.
  • #size is the total amount of seconds.

You can convert a time interval into a string with #to_s or into a float via #to_f.