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DateTimeCalculator

Performs arithmetic on date, time, datetime, and interval values. In Advanced Expression mode, composite expressions involving datetimes and intervals may be constructed.

See also: Date/Time Terminology, Date/Time Format, Date/Time Functions

The DateTimeCalculator performs arithmetic on five temporal types:

- Date
- Time
- Time with UTC offset
- Datetime
- Datetime with UTC offset

The input temporal strings must be in FME format or ISO 8601 format.

DateTimeCalculator also supports interval arithmetic, where the interval can be specified in one of two ways:

- Specified by part. For example, the user can specify 5 for the value of “Years”.
- Specified by an interval string in ISO 8601 duration format.

Invalid temporal and interval input will cause date time functions that consume them to return null, and cause the feature to be rejected.

Limitations:

- Supported temporal range: 0001-01-01 00:00:00.000000000 to 9999-12-31 23:59:59.999999999.
- If the input temporal value contains fractional seconds, only the decimal separator “.” is supported.
- When subtracting a temporal value from another, the two temporal values must have compatible temporal types, or the feature will be rejected. Please see the type compatibility matrix.
- If an interval is specified by parts, then the part values must be either all non-negative, or all non-positive, or the feature will be rejected.

## Input Ports

Accepts and processes features one by one. Temporal values and interval values can come from attributes.

## Output Ports

Outputs valid results.

Outputs invalid results, which are set to null. When features come out of this port, please check if the input strings are valid syntactically, and then if they are valid semantically.

**Note: **Feature order may change in relation to other output ports. Feature order per port is maintained.

## Parameters

Specifies the operation to perform:

- Add or Subtract Interval: add an interval to or subtract it from a temporal value. The interval is specified by part. That is, by years, months, days, hours, minutes, and fractional seconds. Only seconds are allowed to be fractional. The other parts are integers. The parts must be all non-negative or all non-positive, otherwise the feature is rejected. The result has the same temporal type as the input temporal type.
- Add or Subtract Interval (ISO Duration): add an interval to or subtract it from a temporal value. The interval is specified in ISO 8601 duration format. The result has the same temporal type as the input temporal type.
- Calculate Interval between Datetimes: end time minus start time produces an interval. The user can choose to output the interval in ISO 8601 duration format, or as fractional years, months, weeks, days, hours, minutes, or seconds.
- Advanced Expression: datetime functions can be used to construct composite expressions such as @DateTimeAdd(time1, @DateTimeDiff(@Value(time2) – @Value(time3)).

Specify a starting temporal value. Choose whether to add or subtract an interval. Then, specify values for the interval parts of interest. The interval parts supported are years, months, days, hours, minutes, and seconds. The seconds parameter can be fractional. The other part values must be integers.

**Note: **Float values for integer-only fields are rounded into integers.

Specify a starting temporal value. Choose whether to add or subtract an interval. Then, specify the interval with ISO 8601 duration format.

Specify start and end temporal values. Then, pick the output interval type. Supported interval types are:

- ISO 8601 duration format.
- Fractional years, which is calculated as the number of fractional months divided by 12.
- Fractional months: between a start and an end datetime there are a number of full months. The remainder that is not a full month consists of a number of days, hours, minutes, and seconds. The remainder starts in a month that is referred to as a "remainder month". The remainder is first converted into fractional days. Then, the fractional days are divided by the number of days in a remainder month. The remainder month is the month just preceding (and containing a part or all of) the remainder, and guarantees that the remainder is never greater than a month, when expressed as a fractional month. Finally, the remainder as a fractional month is added to the number of full months, to give us the resulting fractional months.
- Example, from 2016-Jan-01 (start) to 2017-Mar-31 (end) there is 1 year and 2 months plus a remainder. 2016-Jan-01 + 1 year + 2 months takes us to 2017-Mar-01, which means that the remainder month is 2017-Mar. That month has 31 days. So, the remainder of 30 days, is divided by 31 to get the fractional month. The total number of months between the two dates are therefore 1 year (12 months) + 2 months + 30/31 months = 14.967742.

- Weeks, days, hours, minutes, seconds: for all of these, we first compute the duration between a start and an end datetime in fractional seconds. Conversion then occurs to the specified unit. There are 60 seconds in a minute. 60 minutes in an hour, 24 hours in a day, and 7 days in a week.

**Note: **To re-use fractional years, months, weeks, days, hours, or minutes in a DateTimeCalculator or @DateTimeAdd(), please round or truncate the fractional values into integers first.

**Tip: **Fractional years, months, weeks, days, hours, minutes, or seconds as the output interval type may be useful for comparison and reporting.

Construct composite FME expressions involving datetime, for example:

- @DateTimeAdd(@Value(newStartDate),@DateTimeDiff(@Value(projEnd),@Value(projStart))
- @DateTimeCast(@DateTimeNow(),time)
- @DateTimeFormat(@DateTimeParse(@Value(sourceString),@Value(inputFormat)),@Value(outputFormat))

Please see FME Date/Time Functions.

## Reference

See also:

## Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

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