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<h1 class="header">Programming Ruby</h1>
<h3 class="subheader">The Pragmatic Programmer's Guide</h3>
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Copyright (c) 2001 by Addison Wesley Longman, Inc. This material may
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presently available at http://www.opencontent.org/openpub/).
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Distribution of substantively modified versions of this document is
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<font color="white" size="7">class NilClass</font>
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Parent:
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<font color="white">Object</font>
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Version:
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1.6
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<p></p>
<H3>Index:</H3>
<i>
<a href="#NilClass._et">&</a>
</i> <i>
<a href="#NilClass._up">^</a>
</i> <i>
<a href="#NilClass._ba">|</a>
</i> <i>
<a href="#NilClass.nil_qm">nil?</a>
</i> <i>
<a href="#NilClass.to_a">to_a</a>
</i> <i>
<a href="#NilClass.to_i">to_i</a>
</i> <i>
<a href="#NilClass.to_s">to_s</a>
</i> <p></p>
<hr>
The class of the singleton object <code>nil</code>.
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<font color="white" size="6">instance methods
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<b>
<a name="NilClass._et">&</a>
</b>
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<code>nil</code>& <i>anObject</i>
-> <code>false</code>
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<P></P>
And---Returns <code>false</code>. As <i>anObject</i> is an
argument to a method call, it is always evaluated; there is no
short-circuit evaluation in this case.
<P></P>
<table class="codebox" cellspacing="0" border="0" cellpadding="3" width="400">
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<pre>
nil && puts("logical and")
nil & puts("and")
</pre>
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<em>produces:</em>
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<pre>
and
</pre>
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<b>
<a name="NilClass._up">^</a>
</b>
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<code>nil</code>^ <i>anObject</i>
-> <code>true</code> or <code>false</code>
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<td></td>
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<P></P>
Exclusive Or---Returns <code>false</code> if <i>anObject</i> is <code>nil</code> or
<code>false</code>,
<code>true</code> otherwise.
<P></P>
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<font size="4">
<b>
<a name="NilClass._ba">|</a>
</b>
</font>
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<td bgcolor="#ffaaaa">
<code>nil</code>| <i>anObject</i>
-> <code>true</code> or <code>false</code>
</td>
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<td></td>
<td>
<P></P>
Or---Returns <code>false</code> if <i>anObject</i> is
<code>nil</code> or <code>false</code>, <code>true</code> otherwise.
<P></P>
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<font size="4">
<b>
<a name="NilClass.nil_qm">nil?</a>
</b>
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<code>nil</code>.nil? -> <code>true</code>
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<P></P>
Always returns <code>true</code>.
<P></P>
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<b>
<a name="NilClass.to_a">to_a</a>
</b>
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<code>nil</code>.to_a -> []
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<P></P>
Always returns an empty array.
<P></P>
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<font size="4">
<b>
<a name="NilClass.to_i">to_i</a>
</b>
</font>
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<td bgcolor="#ffaaaa">
<code>nil</code>.to_i -> 0
</td>
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<td></td>
<td>
<P></P>
Always returns zero.
<P></P>
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<td valign="center" bgcolor="#ff9999">
<font size="4">
<b>
<a name="NilClass.to_s">to_s</a>
</b>
</font>
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<td bgcolor="#ffaaaa">
<code>nil</code>.to_s -> ""
</td>
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<td></td>
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<P></P>
Always returns the empty string.
<P></P>
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<P></P>
<p></p>
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<p></p>
<font size="-1">Extracted from the book "Programming Ruby -
The Pragmatic Programmer's Guide"</font>
<br>
<font size="-3">
Copyright
©
2001 by Addison Wesley Longman, Inc. This material may
be distributed only subject to the terms and conditions set forth in
the Open Publication License, v1.0 or later (the latest version is
presently available at
<a href="http://www.opencontent.org/openpub/">http://www.opencontent.org/openpub/</a>)).
<p></p>
Distribution of substantively modified versions of this document is
prohibited without the explicit permission of the copyright holder.
<p></p>
Distribution of the work or derivative of the work in any standard
(paper) book form is prohibited unless prior permission is obtained
from the copyright holder.
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