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<html><title>Programming Ruby: The Pragmatic Programmer's Guide</title><head><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><STYLE TYPE="text/css"><!--
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</STYLE><table bgcolor="#a03030" cellpadding="3" border="0" cellspacing="0"><tr><td colspan="3"><table bgcolor="#902020" cellpadding="20"><tr><td><h1 class="header">Programming Ruby</h1><h3 class="subheader">The Pragmatic Programmer's Guide</h3></td></tr></table></td></tr><tr><td width="33%" align="left"><a class="subheader" href="ref_c_proc.html">Previous <</a></td><td width="33%" align="center" valign="middle"><a class="subheader" href="builtins.html">Contents ^</a><br></td><td width="33%" align="right"><a class="subheader" href="ref_c_regexp.html">Next ></a><br></td></tr></table></head><body bgcolor="white">
<!--
Copyright (c) 2001 by Addison Wesley Longman. 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
http://www.opencontent.org/openpub/).
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<table><tr><td height="20"><img src="dot.gif" width="1" height="20"></td></tr></table><table border="0" width="100%" bgcolor="660066" cellpadding="10"><tr><td valign="center"><font color="white" size="7">class Range</font></td><td><table border="0"><tr><td><font color="white">
Parent:
</font></td><td><font color="white">Object</font></td></tr><tr><td><font color="white">
Version:
</font></td><td><font color="white">
1.6
</font></td></tr></table></td></tr></table><p></p><H3>Index:</H3><a href="#new">new</a> <a href="#_eq_eq_eq"><i>===</i></a> <a href="#begin"><i>begin</i></a> <a href="#each"><i>each</i></a> <a href="#end"><i>end</i></a> <a href="#exclude_end_qm"><i>exclude_end?</i></a> <a href="#first"><i>first</i></a> <a href="#last"><i>last</i></a> <a href="#length"><i>length</i></a> <a href="#size"><i>size</i></a> <p></p><hr> A <code>Range</code> represents an interval---a set of values with a start
and an end. Ranges may be constructed using the
<em>s</em><code>..</code><em>e</em> and <em>s</em><code>...</code><em>e</em> literals, or
with <a href="ref_c_range.html#new"><code>Range::new</code></a>. Ranges constructed using <code>..</code> run from the
start to the end inclusively. Those created using <code>...</code> exclude the
end value. When used as an iterator, ranges return each value in
the sequence.
<P></P>
<table bgcolor="#fff0f0" cellspacing="0" border="0" cellpadding="3" width="500">
<tr>
<td valign="top"><code>(-1..-5).to_a</code></td>
<td valign="top"></td>
<td valign="top"><code>[]</code></td>
</tr>
<tr>
<td valign="top"><code>(-5..-1).to_a</code></td>
<td valign="top"></td>
<td valign="top"><code>[-5, -4, -3, -2, -1]</code></td>
</tr>
<tr>
<td valign="top"><code>('a'..'e').to_a</code></td>
<td valign="top"></td>
<td valign="top"><code>["a", "b", "c", "d", "e"]</code></td>
</tr>
<tr>
<td valign="top"><code>('a'...'e').to_a</code></td>
<td valign="top"></td>
<td valign="top"><code>["a", "b", "c", "d"]</code></td>
</tr>
</table>
<P></P>
<P></P>
Ranges can be constructed using objects of any type, as long as the
objects can be compared using their <code><=></code> operator and they
support the <code>succ</code> method to return the next object in
sequence.
<P></P>
<table bgcolor="#fff0f0" cellspacing="0" border="0" cellpadding="3" width="500">
<tr>
<td colspan="3" valign="top"><code>class Xs # represent a string of 'x's</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> include Comparable</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> attr :length</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> def initialize(n)</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> @length = n</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> end</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> def succ</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> Xs.new(@length + 1)</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> end</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> def <=>(other)</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> raise TypeError unless other.kind_of? Xs</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> @length <=> other.length</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> end</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> def inspect</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> 'x' * @length</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code> end</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code>end</code></td>
</tr>
<tr>
<td colspan="3" valign="top"><code></code></td>
</tr>
<tr>
<td valign="top"><code>r = Xs.new(3)..Xs.new(6)</code></td>
<td valign="top"></td>
<td valign="top"><code>xxx..xxxxxx</code></td>
</tr>
<tr>
<td valign="top"><code>r.to_a</code></td>
<td valign="top"></td>
<td valign="top"><code>[xxx, xxxx, xxxxx, xxxxxx]</code></td>
</tr>
<tr>
<td valign="top"><code>r.member?(Xs.new(5))</code></td>
<td valign="top"></td>
<td valign="top"><code>true</code></td>
</tr>
</table>
<P></P>
<table border="0" width="100%" cellpadding="10"><tr><td valign="center" colspan="2" bgcolor="990066"><font color="white" size="6">
mixins
</font></td></tr>
<tr><td>Enumerable:
</td><td>
collect, detect, each_with_index, entries, find, find_all, grep,
include?, map, max, member?, min, reject, select, sort, to_a</td></tr>
</table>
<P></P>
<table border="0" width="100%" cellpadding="10"><tr><td valign="center" colspan="2" bgcolor="990066"><font color="white" size="6">class methods
</font></td></tr><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="new"><b>new</b></a></font></td><td bgcolor="#ffaaaa">
Range.new( <i>start</i>,
<i>end</i>, <i>exclusive</i><code>=false</code> )
-> <i>aRange</i>
</td></tr><td></td><td>
<P></P>
Constructs a range using the given <i>start</i> and <i>end</i>. If the
third parameter is omitted or is <code>false</code>, the range will
include the end object; otherwise, it will be excluded.
<P></P>
</td></table>
<P></P>
<table border="0" width="100%" cellpadding="10"><tr><td valign="center" colspan="2" bgcolor="990066"><font color="white" size="6">instance methods
</font></td></tr><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="_eq_eq_eq"><b>===</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i> === <i>anObject</i> -> <code>true</code> or <code>false</code>
</td></tr><td></td><td>
<P></P>
Returns <code>true</code> if <i>anObject</i> is an element of <i>rng</i>,
<code>false</code> otherwise. Conveniently, <code>===</code> is the comparison
operator used by <code>case</code> statements.
<P></P>
<table bgcolor="#fff0f0" cellspacing="0" border="0" cellpadding="3" width="400"><tr><td><pre>
case 79
when 1..50 then print "low\n"
when 51..75 then print "medium\n"
when 76..100 then print "high\n"
end
</pre></td></tr></table>
<em>produces:</em>
<table bgcolor="#fff0f0" cellspacing="0" border="0" cellpadding="3" width="400"><tr><td><pre>
high
</pre></td></tr></table>
<P></P>
</td><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="begin"><b>begin</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i>.begin -> <i>anObject</i>
</td></tr><td></td><td>
<P></P>
Returns the first object of <i>rng</i>.
<P></P>
</td><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="each"><b>each</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i>.each {| i | block }
-> <i>rng</i>
</td></tr><td></td><td>
<P></P>
Iterates over the elements <i>rng</i>, passing each in turn to the
block.
<P></P>
<table bgcolor="#fff0f0" cellspacing="0" border="0" cellpadding="3" width="400"><tr><td><pre>
(10..15).each do |n|
print n, ' '
end
</pre></td></tr></table>
<em>produces:</em>
<table bgcolor="#fff0f0" cellspacing="0" border="0" cellpadding="3" width="400"><tr><td><pre>
10 11 12 13 14 15
</pre></td></tr></table>
<P></P>
</td><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="end"><b>end</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i>.end -> <i>anObject</i>
</td></tr><td></td><td>
<P></P>
Returns the object that defines the end of <i>rng</i>. See also
<a href="ref_c_range.html#length"><code>Range#length</code></a>.
<P></P>
<table bgcolor="#fff0f0" cellspacing="0" border="0" cellpadding="3" width="500">
<tr>
<td valign="top"><code>(1..10).end</code></td>
<td valign="top"></td>
<td valign="top"><code>10</code></td>
</tr>
<tr>
<td valign="top"><code>(1...10).end</code></td>
<td valign="top"></td>
<td valign="top"><code>10</code></td>
</tr>
</table>
<P></P>
<P></P>
</td><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="exclude_end_qm"><b>exclude_end?</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i>.exclude_end?
-> <code>true</code> or <code>false</code>
</td></tr><td></td><td>
<P></P>
Returns <code>true</code> if <i>rng</i> excludes its end value.
<P></P>
</td><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="first"><b>first</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i>.first -> <i>anObject</i>
</td></tr><td></td><td>
<P></P>
Returns the first object in <i>rng</i>.
<P></P>
</td><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="last"><b>last</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i>.last -> <i>anObject</i>
</td></tr><td></td><td>
<P></P>
Synonym for <a href="ref_c_range.html#end"><code>Range#end</code></a>.
<P></P>
</td><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="length"><b>length</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i>.length -> <i>anInteger</i>
</td></tr><td></td><td>
<P></P>
Returns the number of objects in <i>rng</i>.
<P></P>
<table bgcolor="#fff0f0" cellspacing="0" border="0" cellpadding="3" width="500">
<tr>
<td valign="top"><code>(1..10).length</code></td>
<td valign="top"></td>
<td valign="top"><code>10</code></td>
</tr>
<tr>
<td valign="top"><code>(1...10).length</code></td>
<td valign="top"></td>
<td valign="top"><code>9</code></td>
</tr>
</table>
<P></P>
<P></P>
</td><tr><td valign="center" bgcolor="#ff9999"><font size="4"><a name="size"><b>size</b></a></font></td><td bgcolor="#ffaaaa">
<i>rng</i>.size -> <i>anInteger</i>
</td></tr><td></td><td>
<P></P>
Synonym for <a href="ref_c_range.html#length"><code>Range#length</code></a>.
<P></P>
</td></table>
<P></P>
<p></p><hr><table bgcolor="#a03030" cellpadding="10" border="0" cellspacing="0"><tr><td width="33%" align="left"><a class="subheader" href="ref_c_proc.html">Previous <</a></td><td width="33%" align="center" valign="middle"><a class="subheader" href="builtins.html">Contents ^</a><br></td><td width="33%" align="right"><a class="subheader" href="ref_c_regexp.html">Next ></a><br></td></tr></table><p></p><font size="-1">Extracted from the book "Programming Ruby -
The Pragmatic Programmer's Guide"</font><br><font size="-3">
Copyright
©
2000 Addison Wesley Longman, Inc. Released under the terms of the
<a href="http://www.opencontent.org/openpub/">Open Publication License</a> V1.0.
<br>
This reference is available for
<a href="http://www.pragmaticprogrammer.com/ruby/downloads/book.html">download</a>.
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