Class Period

Represents a period of time expressed in human chronological terms: hours, days, weeks, months and so on.
Since 1.0.x
Availability net35-Client
Inheritance
Object
Period
Implements
IEquatable<Period>
Inherited Members
Object.Equals(Object, Object)
Object.ReferenceEquals(Object, Object)
Object.GetType()
Object.MemberwiseClone()
Namespace: NodaTime
Assembly: NodaTime.dll
Syntax
public sealed class Period : IEquatable<Period>
Remarks

A Period contains a set of properties such as Years, Months, and so on that return the number of each unit contained within this period. Note that these properties are not normalized in any way by default, and so a Period may contain values such as "2 hours and 90 minutes". The Normalize() method will convert equivalent periods into a standard representation.

Periods can contain negative units as well as positive units ("+2 hours, -43 minutes, +10 seconds"), but do not differentiate between properties that are zero and those that are absent (i.e. a period created as "10 years" and one created as "10 years, zero months" are equal periods; the Months property returns zero in both cases).

Period equality is implemented by comparing each property's values individually.

Periods operate on calendar-related types such as LocalDateTime whereas Duration operates on instants on the time line. (Note that although ZonedDateTime includes both concepts, it only supports duration-based arithmetic.)

Fields

Zero

A period containing only zero-valued properties.
Since 1.0.x
Availability net35-Client
Declaration
public static readonly Period Zero
Field Value
Type Description
Period

Properties

Days

Gets the number of days within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Days { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

HasDateComponent

Returns whether or not this period contains any non-zero date-based properties (days or higher).
Since 1.0.x
Availability net35-Client
Declaration
public bool HasDateComponent { get; }
Property Value
Type Description
Boolean

HasTimeComponent

Returns whether or not this period contains any non-zero-valued time-based properties (hours or lower).
Since 1.0.x
Availability net35-Client
Declaration
public bool HasTimeComponent { get; }
Property Value
Type Description
Boolean

Hours

Gets the number of hours within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Hours { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

Milliseconds

Gets the number of milliseconds within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Milliseconds { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

Minutes

Gets the number of minutes within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Minutes { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

Months

Gets the number of months within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Months { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

NormalizingEqualityComparer

Returns an equality comparer which compares periods by first normalizing them - so 24 hours is deemed equal to 1 day, and so on. Note that as per the Normalize() method, years and months are unchanged by normalization - so 12 months does not equal 1 year.
Since 1.0.x
Availability net35-Client
Declaration
public static IEqualityComparer<Period> NormalizingEqualityComparer { get; }
Property Value
Type Description
IEqualityComparer<Period>

Seconds

Gets the number of seconds within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Seconds { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

Ticks

Gets the number of ticks within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Ticks { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

Weeks

Gets the number of weeks within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Weeks { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

Years

Gets the number of years within this period.
Since 1.0.x
Availability net35-Client
Declaration
public long Years { get; }
Property Value
Type Description
Int64
Remarks
This property returns zero both when the property has been explicitly set to zero and when the period does not contain this property.

Methods

Between(LocalDate, LocalDate)

Returns the exact difference between two dates.
Since 1.0.x
Availability net35-Client
Declaration
public static Period Between(LocalDate start, LocalDate end)
Parameters
Type Name Description
LocalDate start Start date
LocalDate end End date
Returns
Type Description
Period The period between the two dates, using year, month and day units.
Remarks
If end is before start, each property in the returned period will be negative.

Between(LocalDate, LocalDate, PeriodUnits)

Returns the period between a start and an end date, using only the given units.
Since 1.0.x
Availability net35-Client
Declaration
public static Period Between(LocalDate start, LocalDate end, PeriodUnits units)
Parameters
Type Name Description
LocalDate start Start date
LocalDate end End date
PeriodUnits units Units to use for calculations
Returns
Type Description
Period The period between the given dates, using the given units.
Remarks
If end is before start, each property in the returned period will be negative. If the given set of units cannot exactly reach the end point (e.g. finding the difference between 12th February and 15th March in months) the result will be such that adding it to start will give a value between start and end. In other words, any rounding is "towards start"; this is true whether the resulting period is negative or positive.
Exceptions
Type Condition
ArgumentException units contains time units, is empty or contains unknown values
ArgumentException start and end use different calendars

Between(LocalDateTime, LocalDateTime)

Returns the exact difference between two date/times.
Since 1.0.x
Availability net35-Client
Declaration
public static Period Between(LocalDateTime start, LocalDateTime end)
Parameters
Type Name Description
LocalDateTime start Start date/time
LocalDateTime end End date/time
Returns
Type Description
Period The period between the two date and time values, using all units.
Remarks
If end is before start, each property in the returned period will be negative.

Between(LocalDateTime, LocalDateTime, PeriodUnits)

Returns the period between a start and an end date/time, using only the given units.
Since 1.0.x
Availability net35-Client
Declaration
public static Period Between(LocalDateTime start, LocalDateTime end, PeriodUnits units)
Parameters
Type Name Description
LocalDateTime start Start date/time
LocalDateTime end End date/time
PeriodUnits units Units to use for calculations
Returns
Type Description
Period The period between the given date/times, using the given units.
Remarks
If end is before start, each property in the returned period will be negative. If the given set of units cannot exactly reach the end point (e.g. finding the difference between 1am and 3:15am in hours) the result will be such that adding it to start will give a value between start and end. In other words, any rounding is "towards start"; this is true whether the resulting period is negative or positive.
Exceptions
Type Condition
ArgumentException units is empty or contained unknown values
ArgumentException start and end use different calendars

Between(LocalTime, LocalTime)

Returns the exact difference between two times.
Since 1.0.x
Availability net35-Client
Declaration
public static Period Between(LocalTime start, LocalTime end)
Parameters
Type Name Description
LocalTime start Start time
LocalTime end End time
Returns
Type Description
Period The period between the two times, using the time period units.
Remarks
If end is before start, each property in the returned period will be negative.

Between(LocalTime, LocalTime, PeriodUnits)

Returns the period between a start and an end time, using only the given units.
Since 1.0.x
Availability net35-Client
Declaration
public static Period Between(LocalTime start, LocalTime end, PeriodUnits units)
Parameters
Type Name Description
LocalTime start Start time
LocalTime end End time
PeriodUnits units Units to use for calculations
Returns
Type Description
Period The period between the given times, using the given units.
Remarks
If end is before start, each property in the returned period will be negative. If the given set of units cannot exactly reach the end point (e.g. finding the difference between 3am and 4.30am in hours) the result will be such that adding it to start will give a value between start and end. In other words, any rounding is "towards start"; this is true whether the resulting period is negative or positive.
Exceptions
Type Condition
ArgumentException units contains date units, is empty or contains unknown values
ArgumentException start and end use different calendars

CreateComparer(LocalDateTime)

Creates an System.Collections.Generic.IComparer<T> for periods, using the given "base" local date/time.
Since 1.0.x
Availability net35-Client
Declaration
public static IComparer<Period> CreateComparer(LocalDateTime baseDateTime)
Parameters
Type Name Description
LocalDateTime baseDateTime The base local date/time to use for comparisons.
Returns
Type Description
IComparer<Period> The new comparer.
Remarks
Certain periods can't naturally be compared without more context - how "one month" compares to "30 days" depends on where you start. In order to compare two periods, the returned comparer effectively adds both periods to the "base" specified by baseDateTime and compares the results. In some cases this arithmetic isn't actually required - when two periods can be converted to durations, the comparer uses that conversion for efficiency.

Equals(Period)

Compares the given period for equality with this one.
Since 1.0.x
Availability net35-Client
Declaration
public bool Equals(Period other)
Parameters
Type Name Description
Period other The period to compare this one with.
Returns
Type Description
Boolean True if this period has the same values for the same properties as the one specified.
Remarks
Periods are equal if they contain the same values for the same properties. However, no normalization takes place, so "one hour" is not equal to "sixty minutes".

Equals(Object)

Compares the given object for equality with this one, as per Equals(Period).
Since 1.0.x
Availability net35-Client
Declaration
public override bool Equals(object other)
Parameters
Type Name Description
Object other The value to compare this one with.
Returns
Type Description
Boolean true if the other object is a period equal to this one, consistent with Equals(Period)
Overrides
System.Object.Equals(System.Object)

FromDays(Int64)

Creates a period representing the specified number of days.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromDays(long days)
Parameters
Type Name Description
Int64 days The number of days in the new period
Returns
Type Description
Period A period consisting of the given number of days.

FromHours(Int64)

Creates a period representing the specified number of hours.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromHours(long hours)
Parameters
Type Name Description
Int64 hours The number of hours in the new period
Returns
Type Description
Period A period consisting of the given number of hours.

FromMillseconds(Int64)

Creates a period representing the specified number of miliseconds.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromMillseconds(long milliseconds)
Parameters
Type Name Description
Int64 milliseconds The number of milliseconds in the new period
Returns
Type Description
Period A period consisting of the given number of milliseconds.

FromMinutes(Int64)

Creates a period representing the specified number of minutes.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromMinutes(long minutes)
Parameters
Type Name Description
Int64 minutes The number of minutes in the new period
Returns
Type Description
Period A period consisting of the given number of minutes.

FromMonths(Int64)

Creates a period representing the specified number of months.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromMonths(long months)
Parameters
Type Name Description
Int64 months The number of months in the new period
Returns
Type Description
Period A period consisting of the given number of months.

FromSeconds(Int64)

Creates a period representing the specified number of seconds.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromSeconds(long seconds)
Parameters
Type Name Description
Int64 seconds The number of seconds in the new period
Returns
Type Description
Period A period consisting of the given number of seconds.

FromTicks(Int64)

Creates a period representing the specified number of ticks.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromTicks(long ticks)
Parameters
Type Name Description
Int64 ticks The number of ticks in the new period
Returns
Type Description
Period A period consisting of the given number of ticks.

FromWeeks(Int64)

Creates a period representing the specified number of weeks.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromWeeks(long weeks)
Parameters
Type Name Description
Int64 weeks The number of weeks in the new period
Returns
Type Description
Period A period consisting of the given number of weeks.

FromYears(Int64)

Creates a period representing the specified number of years.
Since 1.0.x
Availability net35-Client
Declaration
public static Period FromYears(long years)
Parameters
Type Name Description
Int64 years The number of years in the new period
Returns
Type Description
Period A period consisting of the given number of years.

GetHashCode()

Returns the hash code for this period, consistent with Equals(Period).
Since 1.0.x
Availability net35-Client
Declaration
public override int GetHashCode()
Returns
Type Description
Int32 The hash code for this period.
Overrides
System.Object.GetHashCode()

Normalize()

Returns a normalized version of this period, such that equivalent (but potentially non-equal) periods are changed to the same representation.
Since 1.0.x
Availability net35-Client
Declaration
public Period Normalize()
Returns
Type Description
Period The normalized period.
Remarks
Months and years are unchanged (as they can vary in length), but weeks are multiplied by 7 and added to the Days property, and all time properties are normalized to their natural range (where ticks are "within a millisecond"), adding to the larger property where necessary. So for example, a period of 25 hours becomes a period of 1 day and 1 hour. Aside from months and years, either all the properties end up positive, or they all end up negative.
Exceptions
Type Condition
System.OverflowException The period doesn't have years or months, but it contains more than System.Int64.MaxValue ticks when the combined weeks/days/time portions are considered. Such a period could never be useful anyway, however. In some cases this may occur even though the theoretical result would be valid due to balancing positive and negative values, but for simplicity there is no attempt to work around this - in realistic periods, it shouldn't be a problem.
See Also

ToBuilder()

Creates a PeriodBuilder from this instance. The new builder is populated with the values from this period, but is then detached from it: changes made to the builder are not reflected in this period.
Since 1.0.x
Availability net35-Client
Declaration
public PeriodBuilder ToBuilder()
Returns
Type Description
PeriodBuilder A builder with the same values and units as this period.

ToDuration()

For periods that do not contain a non-zero number of years or months, returns a duration for this period assuming a standard 7-day week, 24-hour day, 60-minute hour etc.
Since 1.0.x
Availability net35-Client
Declaration
public Duration ToDuration()
Returns
Type Description
Duration The duration of the period.
Exceptions
Type Condition
System.InvalidOperationException The month or year property in the period is non-zero.
System.OverflowException The period doesn't have years or months, but the calculation overflows the bounds of Duration. In some cases this may occur even though the theoretical result would be valid due to balancing positive and negative values, but for simplicity there is no attempt to work around this - in realistic periods, it shouldn't be a problem.

ToString()

Returns this string formatted according to the RoundtripPattern.
Since 1.0.x
Availability net35-Client
Declaration
public override string ToString()
Returns
Type Description
String A formatted representation of this period.
Overrides
System.Object.ToString()

Operators

Addition(Period, Period)

Adds two periods together, by simply adding the values for each property.
Since 1.0.x
Availability net35-Client
Declaration
public static Period operator +(Period left, Period right)
Parameters
Type Name Description
Period left The first period to add
Period right The second period to add
Returns
Type Description
Period The sum of the two periods. The units of the result will be the union of those in both periods.

Subtraction(Period, Period)

Subtracts one period from another, by simply subtracting each property value.
Since 1.0.x
Availability net35-Client
Declaration
public static Period operator -(Period minuend, Period subtrahend)
Parameters
Type Name Description
Period minuend The period to subtract the second operand from
Period subtrahend The period to subtract the first operand from
Returns
Type Description
Period The result of subtracting all the values in the second operand from the values in the first. The units of the result will be the union of both periods, even if the subtraction caused some properties to become zero (so "2 weeks, 1 days" minus "2 weeks" is "zero weeks, 1 days", not "1 days").

Implements

System.IEquatable<T>