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<HTML><HEAD><TITLE>Recipe 4.9. Appending One Array to Another (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="1999-07-02T01:31:55Z"><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="ch04_01.htm"TITLE="4. Arrays"><LINKREL="prev"HREF="ch04_09.htm"TITLE="4.8. Computing Union, Intersection, or Difference of Unique Lists"><LINKREL="next"HREF="ch04_11.htm"TITLE="4.10. Reversing an Array"></HEAD><BODYBGCOLOR="#FFFFFF"><img alt="Book Home" border="0" src="gifs/smbanner.gif" usemap="#banner-map" /><map name="banner-map"><area shape="rect" coords="1,-2,616,66" href="index.htm" alt="Perl Cookbook"><area shape="rect" coords="629,-11,726,25" href="jobjects/fsearch.htm" alt="Search this book" /></map><div class="navbar"><p><TABLEWIDTH="684"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="228"><ACLASS="sect1"HREF="ch04_09.htm"TITLE="4.8. Computing Union, Intersection, or Difference of Unique Lists"><IMGSRC="../gifs/txtpreva.gif"ALT="Previous: 4.8. Computing Union, Intersection, or Difference of Unique Lists"BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="228"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1"><ACLASS="chapter"REL="up"HREF="ch04_01.htm"TITLE="4. Arrays"></A></FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="228"><ACLASS="sect1"HREF="ch04_11.htm"TITLE="4.10. Reversing an Array"><IMGSRC="../gifs/txtnexta.gif"ALT="Next: 4.10. Reversing an Array"BORDER="0"></A></TD></TR></TABLE></DIV><DIVCLASS="sect1"><H2CLASS="sect1"><ACLASS="title"NAME="ch04-33245">4.9. Appending One Array to Another</A></H2><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch04-pgfId-825">Problem <ACLASS="indexterm"NAME="ch04-idx-1000006687-0"></A><ACLASS="indexterm"NAME="ch04-idx-1000006687-1"></A><ACLASS="indexterm"NAME="ch04-idx-1000006687-2"></A></A></H3><PCLASS="para">You want to join two arrays by appending all the elements of one to the end of the other.</P></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch04-pgfId-831">Solution</A></H3><PCLASS="para">Use <CODECLASS="literal">push</CODE>:</P><PRECLASS="programlisting"># pushpush(@ARRAY1, @ARRAY2);</PRE></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch04-pgfId-841">Discussion</A></H3><PCLASS="para">The <CODECLASS="literal">push</CODE> function is optimized for appending a list to the end of an array. You can take advantage of Perl's list flattening to join two arrays, but it results in significantly more copying than <CODECLASS="literal">push</CODE>:</P><PRECLASS="programlisting">@ARRAY1 = (@ARRAY1, @ARRAY2);</PRE><PCLASS="para">Here's an example of <CODECLASS="literal">push</CODE> in action:</P><PRECLASS="programlisting">@members = ("Time", "Flies");@initiates = ("An", "Arrow");push(@members, @initiates);# @members is now ("Time", "Flies", "An", "Arrow")</PRE><PCLASS="para">If you want to insert the elements of one array into the middle of another, use the <CODECLASS="literal">splice</CODE> function:</P><PRECLASS="programlisting">splice(@members, 2, 0, "Like", @initiates);print "@members\n";splice(@members, 0, 1, "Fruit");splice(@members, -2, 2, "A", "Banana");print "@members\n";</PRE><PCLASS="para">This is output:</P><PRECLASS="programlisting"><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>Time Flies Like An Arrow</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>Fruit Flies Like A Banana</I></CODE></B></CODE></PRE></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch04-pgfId-865">See Also</A></H3><PCLASS="para">The <CODECLASS="literal">splice</CODE> and <CODECLASS="literal">push</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>; the <ACLASS="olink"HREF="../prog/ch02_03.htm#PERL2-CH-2-SECT-3.4">"List Values and Arrays"</A> section of <ACLASS="olink"HREF="../prog/ch02_01.htm">Chapter 2</A> of <ACLASS="citetitle"HREF="../prog/index.htm"TITLE="Programming Perl"><CITECLASS="citetitle">Programming Perl</CITE></A>; the "List Value Constructors" section of <ICLASS="filename">perldata </I>(1)</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="ch04_09.htm"TITLE="4.8. 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