64 lines
3.4 KiB
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64 lines
3.4 KiB
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<!DOCTYPE HTML PUBLIC "-//W3O//DTD W3 HTML 2.0//EN">
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<!Converted with LaTeX2HTML 0.6.5 (Tue Nov 15 1994) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds >
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<HEAD>
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<TITLE>17. Arrays</TITLE>
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</HEAD>
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<BODY>
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<meta name="description" value=" Arrays">
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<meta name="keywords" value="clm">
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<meta name="resource-type" value="document">
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<meta name="distribution" value="global">
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<P>
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<b>Common Lisp the Language, 2nd Edition</b>
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<BR> <HR><A NAME=tex2html3483 HREF="node158.html"><IMG ALIGN=BOTTOM ALT="next" SRC="icons/next_motif.gif"></A> <A NAME=tex2html3481 HREF="clm.html"><IMG ALIGN=BOTTOM ALT="up" SRC="icons/up_motif.gif"></A> <A NAME=tex2html3475 HREF="node156.html"><IMG ALIGN=BOTTOM ALT="previous" SRC="icons/previous_motif.gif"></A> <A NAME=tex2html3485 HREF="node1.html"><IMG ALIGN=BOTTOM ALT="contents" SRC="icons/contents_motif.gif"></A> <A NAME=tex2html3486 HREF="index.html"><IMG ALIGN=BOTTOM ALT="index" SRC="icons/index_motif.gif"></A> <BR>
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<B> Next:</B> <A NAME=tex2html3484 HREF="node158.html"> Array Creation</A>
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<B>Up:</B> <A NAME=tex2html3482 HREF="clm.html">Common Lisp the Language</A>
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<B> Previous:</B> <A NAME=tex2html3476 HREF="node156.html"> Primitive Hash Function</A>
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<HR> <P>
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<H1><A NAME=SECTION002100000000000000000>17. Arrays</A></H1>
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<P>
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An array is an object with components arranged according
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to a rectilinear coordinate system.
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In principle, an
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array in Common Lisp may have any number of dimensions, including zero.
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(A zero-dimensional array has exactly one element.)
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In practice, an implementation may limit the number of dimensions
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supported, but
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every Common Lisp implementation must support arrays of up to
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seven dimensions.
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Each dimension is a non-negative integer; if any dimension of an array is zero,
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the array has no elements.
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<P>
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An array may be a <i>general array</i>, meaning each element may be any Lisp
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object, or it may be a <i>specialized array</i>, meaning that each element
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must be of a given restricted type.
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<P>
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<img align=bottom alt="old_change_begin" src="gif/old_change_begin.gif"><br>
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One-dimensional arrays are called vectors. General vectors may contain
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any Lisp object. Vectors whose elements are restricted to type
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<tt>string-char</tt> are called <i>strings</i>. Vectors whose elements are
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restricted to type <tt>bit</tt> are called <i>bit-vectors</i>.
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<br><img align=bottom alt="old_change_end" src="gif/old_change_end.gif">
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<P>
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<img align=bottom alt="change_begin" src="gif/change_begin.gif"><br>
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X3J13 voted in March 1989 (CHARACTER-PROPOSAL) <A NAME=17508> </A>
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to eliminate the type <tt>string-char</tt> and to redefine the type
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<tt>string</tt> to be the union of one or more specialized vector
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types, the types of whose elements are subtypes of the type <tt>character</tt>.
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<br><img align=bottom alt="change_end" src="gif/change_end.gif">
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<P>
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<HR>
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<UL>
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<LI> <A NAME=tex2html3487 HREF="node158.html#SECTION002110000000000000000"> Array Creation</A>
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<LI> <A NAME=tex2html3488 HREF="node159.html#SECTION002120000000000000000"> Array Access</A>
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<LI> <A NAME=tex2html3489 HREF="node160.html#SECTION002130000000000000000"> Array Information</A>
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<LI> <A NAME=tex2html3490 HREF="node161.html#SECTION002140000000000000000"> Functions on Arrays of Bits</A>
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<LI> <A NAME=tex2html3491 HREF="node162.html#SECTION002150000000000000000"> Fill Pointers</A>
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<LI> <A NAME=tex2html3492 HREF="node163.html#SECTION002160000000000000000"> Changing the Dimensions of an Array</A>
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</UL>
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<HR>
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<P><ADDRESS>
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AI.Repository@cs.cmu.edu
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</ADDRESS>
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</BODY>
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