DateObject

Description Options See Also

Description

DateObjects are used to consistently store date information for a variable.  DateObject variables are used only when time series data is being analyzed.  The user sees DateObjects as human-decipherable strings based on the type of dates being stored; all internal calculations, however, reduce DateObjects to double-precision floating point values.

The DateObject's conversion to double-precision is dependent on the both the type of date being stored and the position of that object in the variable table.  The first DateObject in a variable acts as the base for all subsequent DateObjects.  The first DateObject is equal to 0.0 when converting to double-precision.  All other DateObject conversions are computed based on the number of date units from the base.  For example, consider a monthly data set starting at April, 1979:

DateObject String Representation Time from Base Double Precision Equivalent
4/1979 0 (This is the base) 0.0

Choosing future months, the conversions will be as follows:

DateObject String Representation Time from Base Double Precision Equivalent
9/1979 5 months 5.0
10/1981 2 years 6 months 30.0

The same conversions are used for all DateObject types, which are described below.

Options

DateObject values can be of multiple types:

Type Description
Annual Annual data, storing years alone
Quarterly Four quarters per year, represented as Q#/####
Monthly Twelve months per year, as shown in the preceding example
Bi-Monthly Twenty four bi-montly periods per year
Weekly Fifty two periods per year
Daily True date tracking, including leap year accounting

See Also

New Time Series
Import Time Series
Data Window
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