View source for Date and Time Values

[[Category:Analytica User Guide]]
[[Category: Date formats]]

<breadcrumbs>Analytica User Guide > Expressions > {{PAGENAME}}</breadcrumbs>
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Dates and times are treated as [[Numbers|numeric]] quantities, denoting the number of days elapsed since the date origin (usually 1-Jan-1904, or 1-Jan-1900 if the ''Use Excel date origin ''preference is checked). Dates can be entered directly into an [[Expression Syntax|expression]], at any point in an expression and regardless of the number format setting, using the syntax ''d-MMM-yyyy'', such as <code>27-Jan-2010</code>, using a 3-letter English-language month abbreviation. Times can be entered in the format ''hh:mm:ss [tt]'', such as <code>10:27:00pm</code> or <code>22:27:00</code>, which becomes a fractional value between 0 and 1. A combined date-time can be entered as, e.g., <code>27-Jan-2010 10:27:00pm</code>. In the general case, you cannot enter other date formats within an expression. For example, <code>1/27/2010</code> would be interpreted as two divide operators, <code>(1/27)/2010</code>, and regional (non-English) month names, e.g., <code>27-Ene-2010</code>, are not recognized.

You can enter dates and times in more general formats, and in region/culture-specific styles, when the number format is set to ''Date ''and the date, time or date-time is the only element appearing in the expression. In this case, Analytica recognizes almost all commonly used formats, such as <code>27-January-2010</code>, <code>1/27/2010</code>, <code>1-27-2010</code>, or <code>Jan 27, 2010</code>. When you enter a date in a format such as <code>1/2/2010</code> or <code>1-2-2010</code>, the date is interpreted based on your regional setting. For example, in the US, these would parse to 2-Jan-2010, while in Europe they would generally parse as 1-Feb-2010. Non-English month names are also recognized in languages that use characters only from the standard Analytica character page (which includes most western European languages). For example, <code>27-Enero-2010</code> is recognized if you are in Spain.

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'''ISO 8601 date-times and time zones''' ''(new to [[Analytica 7.2]])'': You can also enter a date or date-time in the ISO 8601 form <code>yyyy-MM-dd</code> or <code>yyyy-MM-ddTHH:mm:ss</code> (with optional fractional seconds) anywhere in an expression, e.g., <code>Sequence(2025-08-25T00:00:00, 2025-08-27T00:00:00, dateUnit: 'D')</code>. The month and day must each be two digits, so <code>2025-8-25</code> inside an expression is still two subtractions. A UTC offset written directly after the time, <code>Z</code>, <code>+HH:MM</code>, <code>+HHMM</code> or <code>+HH</code> (with either sign), is part of the literal, e.g., <code>2025-08-25T00:07:05.000+0000</code>; a space before the sign makes it ordinary arithmetic, as in <code>2025-08-25T00:07:05 + 01:30</code>.

A date-time value itself has no time zone. The model's [[System variables#Sys_TimeZone|Sys_TimeZone]] system variable (default <code>'Local'</code>, this computer's zone; also on the [[Preferences dialog]]) says which zone the model's date-times are in. A literal or parsed text that carries an offset is converted into that zone, so <code>2025-08-25T00:07:05Z</code> is 24-Aug-2025 17:07:05 in a model whose zone is US Pacific. Values without an offset are taken as already being in the model's zone and are never converted. See [[Date Functions]], [[ParseDate]] and [[NumberToText]] (the <code>ISO8601</code> output format).
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==See Also==
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* [[Objects and values]]
* [[Special handling of date values]]
* [[Tutorial_videos#Manipulating_Dates_in_Analytica|Manipulating Dates in Analytica]] (a video tutorial and a downloadable model)
* [[Date formats]]
* [[Number_format#Date_format|Date format]]
* [[Date functions]]
* [[Date Functions]]
* [[Time index]]
* [[Dynamic]]
</div>


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