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<html><head><title>XLISP remove</title>
<link rel="stylesheet" type="text/css" href="reference.css">
</head>
<body>
<a href="../start.htm">Nyquist / XLISP 2.0</a> -
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<a href="../examples/examples.htm">Examples</a> |
<a href="reference-index.htm">Reference</a>
<hr>
<h1>remove</h1>
<hr>
<p><table cellpadding="0" cellspacing="0" style="margin-left:10px"><tbody>
<tr valign="top">
<td><nobr>Type:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>function (subr)</nobr></td>
</tr>
<tr valign="top">
<td><nobr>Source:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>xllist.c</nobr></td>
</tr>
</tbody></table></p>
<h2>Syntax</h2>
<dl>
<dt>(remove <i>expr list-expr</i> [{:test | :test-not} <i>test</i>])</dt>
<dd><i>expr</i> - the expression to remove, an atom or list<br>
<i>list-expr</i> - the list to remove from<br>
<i>test</i> - optional test function, default is
<a href="eql.htm">eql</a><br>
returns - a copy of <i>list-expr</i> with matching expressions removed</dd>
</dl>
<h2>Description</h2>
<p>The 'remove' function searches through 'list-expr' for 'expr'. If 'expr'
is found, 'remove' returns the list with the 'expr' deleted. All occurances
of 'expr' are deleted. If 'expr' is not found, then the 'list-expr' is
returned unaltered. You may specify your own test with the ':test' and
':test-not' keywords followed by the test you which to perform. Note that
this operation is non-destructive, it does not modify or affect 'list-expr'
directly, it creates a modified copy.</p>
<h2>Examples</h2>
<pre class="example">
(setq mylist '(a b c d it e f)) <font color="#008844">; set up a list</font>
(remove 'it mylist) <font color="#008844">; returns (A B C D E F)</font>
(print mylist) <font color="#008844">; prints (A B C D IT E F)</font>
<font color="#008844">; note that MYLIST is not affected</font>
(setq mylist '(a b c b d b)) <font color="#008844">; change list to include duplicates</font>
(remove 'b mylist) <font color="#008844">; returns (A C D)</font>
(setq alist '( (a) (b) (it) (c))) <font color="#008844">; set up another list</font>
(remove '(it) alist) <font color="#008844">; returns ((A) (B) (IT) (C))</font>
<font color="#008844">; the EQ test doesn't work for lists</font>
(remove '(it) alist :test 'equal) <font color="#008844">; returns ((A) (B) (C))</font>
(setq slist '( "a" "b" "it" "c")) <font color="#008844">; set up yet another list</font>
(remove "it" slist) <font color="#008844">; returns ("a" "b" "c")</font>
(remove "it" slist :test-not 'equal) <font color="#008844">; returns ("it")</font>
<font color="#008844">; REMOVE takes away everything but IT</font>
</pre>
<p><b>Note:</b> The 'remove' function can work with a list or string as the
'expr'. However, the default <a href="eql.htm">eql</a> test does
not work with lists or strings, only symbols and numbers. To make this work,
you need to use the ':test' keyword along with
<a href="equal.htm">equal</a> for 'test'.</p>
<p><b>Common Lisp:</b> XLISP does not support the ':from-end', ':start',
':end', ':count' and ':key' keywords which Common Lisp does.</p>
<p>See the
<a href="../manual/xlisp-man-016.htm#remove">remove</a>
function in the <nobr>XLISP 2.0</nobr> manual.</p>
<p><nobr> <a href="#top">Back to Top</nobr></a></p>
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