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<HTML><HEAD><TITLE>Recipe 3.8. Printing a Date (Perl Cookbook)</TITLE><METANAME="DC.title"CONTENT="Perl Cookbook"><METANAME="DC.creator"CONTENT="Tom Christiansen & Nathan Torkington"><METANAME="DC.publisher"CONTENT="O'Reilly & Associates, Inc."><METANAME="DC.date"CONTENT="1999-07-02T01:30:42Z"><METANAME="DC.type"CONTENT="Text.Monograph"><METANAME="DC.format"CONTENT="text/html"SCHEME="MIME"><METANAME="DC.source"CONTENT="1-56592-243-3"SCHEME="ISBN"><METANAME="DC.language"CONTENT="en-US"><METANAME="generator"CONTENT="Jade 1.1/O'Reilly DocBook 3.0 to HTML 4.0"><LINKREV="made"HREF="mailto:online-books@oreilly.com"TITLE="Online Books Comments"><LINKREL="up"HREF="ch03_01.htm"TITLE="3. Dates and Times"><LINKREL="prev"HREF="ch03_08.htm"TITLE="3.7. Parsing Dates and Times from Strings"><LINKREL="next"HREF="ch03_10.htm"TITLE="3.9. 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High-Resolution Timers"BORDER="0"></A></TD></TR></TABLE></DIV><DIVCLASS="sect1"><H2CLASS="sect1"><ACLASS="title"NAME="ch03-19035">3.8. Printing a Date</A></H2><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch03-pgfId-646">Problem <ACLASS="indexterm"NAME="ch03-idx-1000006341-0"></A><ACLASS="indexterm"NAME="ch03-idx-1000006341-1"></A></A></H3><PCLASS="para">You need to print a date and time shown in Epoch seconds format in human-readable form.</P></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch03-pgfId-652">Solution</A></H3><PCLASS="para">Simply call <CODECLASS="literal">localtime</CODE><ACLASS="indexterm"NAME="ch03-idx-1000006348-0"></A><ACLASS="indexterm"NAME="ch03-idx-1000006348-1"></A> or <CODECLASS="literal">gmtime</CODE> in scalar context, which takes an Epoch second value and returns a string of the form <CODECLASS="literal">Tue</CODE> <CODECLASS="literal">May</CODE> <CODECLASS="literal">26</CODE> <CODECLASS="literal">05:15:20</CODE> <CODECLASS="literal">1998</CODE>:</P><PRECLASS="programlisting">$STRING = localtime($EPOCH_SECONDS);</PRE><PCLASS="para">Alternatively, the <CODECLASS="literal">strftime</CODE><ACLASS="indexterm"NAME="ch03-idx-1000006347-0"></A> function in the standard POSIX module supports a more customizable output format, and takes individual DMYHMS values:</P><PRECLASS="programlisting">use POSIX qw(strftime);$STRING = strftime($FORMAT, $SECONDS, $MINUTES, $HOUR, $DAY_OF_MONTH, $MONTH, $YEAR, $WEEKDAY, $YEARDAY, $DST);</PRE><PCLASS="para">The CPAN module Date::Manip has a <CODECLASS="literal">UnixDate</CODE> routine that works like a specialized form <CODECLASS="literal">sprintf</CODE> designed to handle dates. Pass it a Date::Manip date value. Using Date::Manip in lieu of POSIX::strftime has the advantage of not requiring a POSIX-compliant system.</P><PRECLASS="programlisting">use Date::Manip qw(UnixDate);$STRING = UnixDate($DATE, $FORMAT);</PRE></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch03-pgfId-676">Discussion</A></H3><PCLASS="para">The simplest solution is built into Perl already: the <CODECLASS="literal">localtime</CODE> function. In scalar context, it returns the string formatted in a particular way:</P><PRECLASS="programlisting"><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>Sun Sep 21 15:33:36 1997</I></CODE></B></CODE></PRE><PCLASS="para">This makes for simple code, although it restricts the format of the string:</P><PRECLASS="programlisting">use Time::Local;$time = timelocal(50, 45, 3, 18, 0, 73);print "Scalar localtime gives: ", scalar(localtime($time)), "\n";<CODECLASS="userinput"><B><CODECLASS="replaceable"><I>Scalar localtime gives: Thu Jan 18 03:45:50 1973</I></CODE></B></CODE></PRE><PCLASS="para">Of course, <CODECLASS="literal">localtime</CODE> requires the date and time in Epoch seconds. The <CODECLASS="literal">POSIX::strftime</CODE> function takes a set of individual DMYMHS values and a format and returns a string. The format is similar to a <CODECLASS="literal">printf</CODE> format; <CODECLASS="literal">%</CODE> directives specify fields in the output string. A full list of these directives is available in your system's documentation for <CODECLASS="literal">strftime</CODE>. <CODECLASS="literal">strftime</CODE> expects the individual values representing the date and time to be the same range as the values returned by <CODECLASS="literal">localtime</CODE>:</P><PRECLASS="programlisting">use POSIX qw(strftime);use Time::Local;$time = timelocal(50, 45, 3, 18, 0, 73);print "strftime gives: ", strftime("%A %D", localtime($time)), "\n";<CODECLASS="userinput"><B><CODECLASS="replaceable"><I>strftime gives: Thursday 01/18/73</I></CODE></B></CODE></PRE><PCLASS="para">All values are shown in their national representation when using POSIX::strftime. So, if you run it in France, your program would print <CODECLASS="literal">"Sunday"</CODE> as <CODECLASS="literal">"Dimanche"</CODE>. Be warned: Perl's interface to the POSIX function <CODECLASS="literal">strftime</CODE> always converts the date, assuming that it falls in the current time zone.</P><PCLASS="para">If you don't have access to POSIX's <CODECLASS="literal">strftime</CODE> function, there's always the trusty <ACLASS="indexterm"NAME="ch03-idx-1000006354-0"></A>Date::Manip CPAN module, described in <ACLASS="xref"HREF="ch03_07.htm"TITLE="Day in a Week/Month/Year or Week Number">Recipe 3.6</A>.</P><PRECLASS="programlisting">use Date::Manip qw(ParseDate UnixDate);$date = ParseDate("18 Jan 1973, 3:45:50");$datestr = UnixDate($date, "%a %b %e %H:%M:%S %z %Y"); # as scalarprint "Date::Manip gives: $datestr\n";<CODECLASS="userinput"><B><CODECLASS="replaceable"><I>Date::Manip gives: Thu Jan 18 03:45:50 GMT 1973</I></CODE></B></CODE><CODECLASS="literal"></CODE><ACLASS="indexterm"NAME="ch03-idx-1000006350-0"></A></PRE></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch03-pgfId-724">See Also</A></H3><PCLASS="para">The <CODECLASS="literal">gmtime</CODE> and <CODECLASS="literal">localtime</CODE> functions in <EMCLASS="emphasis">perlfunc </EM>(1) and <ACLASS="olink"HREF="../prog/ch03_01.htm">Chapter 3</A> of <ACLASS="citetitle"HREF="../prog/index.htm"TITLE="Programming Perl"><CITECLASS="citetitle">Programming Perl</CITE></A>; <ICLASS="filename">perllocale </I>(1); your system's <ICLASS="filename">strftime </I>(3) manpage; the documentation for the POSIX module (also in <ACLASS="olink"HREF="../prog/ch07_01.htm">Chapter 7</A> of <ACLASS="citetitle"HREF="../prog/index.htm"TITLE="Programming Perl"><CITECLASS="citetitle">Programming Perl</CITE></A>); the documentation for the CPAN module Date::Manip <ACLASS="indexterm"NAME="ch03-idx-1000006343-0"></A><ACLASS="indexterm"NAME="ch03-idx-1000006343-1"></A></P></DIV></DIV><DIVCLASS="htmlnav"><P></P><HRALIGN="LEFT"WIDTH="684"TITLE="footer"><TABLEWIDTH="684"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="228"><ACLASS="sect1"HREF="ch03_08.htm"TITLE="3.7. 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