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| 55 | <H1><A NAME="SECTION0081000000000000000000"> |
| 56 | 6.10 <tt class="module">datetime</tt> -- |
| 57 | Basic date and time types</A> |
| 58 | </H1> |
| 59 | |
| 60 | <P> |
| 61 | <A NAME="module-datetime"></A> |
| 62 | |
| 63 | <P> |
| 64 | |
| 65 | <span class="versionnote">New in version 2.3.</span> |
| 66 | |
| 67 | <P> |
| 68 | The <tt class="module">datetime</tt> module supplies classes for manipulating dates |
| 69 | and times in both simple and complex ways. While date and time |
| 70 | arithmetic is supported, the focus of the implementation is on |
| 71 | efficient member extraction for output formatting and manipulation. |
| 72 | |
| 73 | <P> |
| 74 | There are two kinds of date and time objects: ``naive'' and ``aware''. |
| 75 | This distinction refers to whether the object has any notion of time |
| 76 | zone, daylight saving time, or other kind of algorithmic or political |
| 77 | time adjustment. Whether a naive <tt class="class">datetime</tt> object represents |
| 78 | Coordinated Universal Time (UTC), local time, or time in some other |
| 79 | timezone is purely up to the program, just like it's up to the program |
| 80 | whether a particular number represents metres, miles, or mass. Naive |
| 81 | <tt class="class">datetime</tt> objects are easy to understand and to work with, at |
| 82 | the cost of ignoring some aspects of reality. |
| 83 | |
| 84 | <P> |
| 85 | For applications requiring more, <tt class="class">datetime</tt> and <tt class="class">time</tt> |
| 86 | objects have an optional time zone information member, |
| 87 | <tt class="member">tzinfo</tt>, that can contain an instance of a subclass of |
| 88 | the abstract <tt class="class">tzinfo</tt> class. These <tt class="class">tzinfo</tt> objects |
| 89 | capture information about the offset from UTC time, the time zone |
| 90 | name, and whether Daylight Saving Time is in effect. Note that no |
| 91 | concrete <tt class="class">tzinfo</tt> classes are supplied by the <tt class="module">datetime</tt> |
| 92 | module. Supporting timezones at whatever level of detail is required |
| 93 | is up to the application. The rules for time adjustment across the |
| 94 | world are more political than rational, and there is no standard |
| 95 | suitable for every application. |
| 96 | |
| 97 | <P> |
| 98 | The <tt class="module">datetime</tt> module exports the following constants: |
| 99 | |
| 100 | <P> |
| 101 | <dl><dt><b><tt id='l2h-1856' xml:id='l2h-1856'>MINYEAR</tt></b></dt> |
| 102 | <dd> |
| 103 | The smallest year number allowed in a <tt class="class">date</tt> or |
| 104 | <tt class="class">datetime</tt> object. <tt class="constant">MINYEAR</tt> |
| 105 | is <code>1</code>. |
| 106 | </dd></dl> |
| 107 | |
| 108 | <P> |
| 109 | <dl><dt><b><tt id='l2h-1857' xml:id='l2h-1857'>MAXYEAR</tt></b></dt> |
| 110 | <dd> |
| 111 | The largest year number allowed in a <tt class="class">date</tt> or <tt class="class">datetime</tt> |
| 112 | object. <tt class="constant">MAXYEAR</tt> is <code>9999</code>. |
| 113 | </dd></dl> |
| 114 | |
| 115 | <P> |
| 116 | <div class="seealso"> |
| 117 | <p class="heading">See Also:</p> |
| 118 | |
| 119 | <dl compact="compact" class="seemodule"> |
| 120 | <dt>Module <b><tt class="module"><a href="module-calendar.html">calendar</a></tt>:</b> |
| 121 | <dd>General calendar related functions. |
| 122 | </dl> |
| 123 | <dl compact="compact" class="seemodule"> |
| 124 | <dt>Module <b><tt class="module"><a href="module-time.html">time</a></tt>:</b> |
| 125 | <dd>Time access and conversions. |
| 126 | </dl> |
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| 128 | |
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| 134 | <A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a> |
| 135 | |
| 136 | <UL CLASS="ChildLinks"> |
| 137 | <LI><A href="node251.html">6.10.1 Available Types</a> |
| 138 | <LI><A href="datetime-timedelta.html">6.10.2 <tt class="class">timedelta</tt> Objects</a> |
| 139 | <LI><A href="datetime-date.html">6.10.3 <tt class="class">date</tt> Objects</a> |
| 140 | <LI><A href="datetime-datetime.html">6.10.4 <tt class="class">datetime</tt> Objects</a> |
| 141 | <LI><A href="datetime-time.html">6.10.5 <tt class="class">time</tt> Objects</a> |
| 142 | <LI><A href="datetime-tzinfo.html">6.10.6 <tt class="class">tzinfo</tt> Objects</a> |
| 143 | <LI><A href="node257.html">6.10.7 <tt class="method">strftime()</tt> Behavior</a> |
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| 182 | <span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span> |
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