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关于嵌入式编程的tcl语法的资料

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<pre>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">
~/tcltk$<b> tclsh</b>
% <b>set Phrase "hello, world!"</b>
hello, world!
 
% <b>string toupper $Phrase</b>
HELLO, WORLD!
 
% <b>string totitle $Phrase</b>
Hello, world!
 
% <b>string match ello $Phrase</b>
0

% <b>string match *ello* $Phrase</b>
1

% <b>string length $Phrase</b>
14 

% <b>append Phrase "Nice day, eh?"</b>
hello, world!
Nice day, eh?

% <b>string toupper $Phrase</b>
HELLO, WORLD!
NICE DAY, EH? 

% <b>string wordend $Phrase 7</b>
12
			</code>
</pre>
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<td width="90%"><font size="4" face="Verdana, Arial, Helvetica"><b>Tcl 字符串和模式匹配</b></font></td><td width="200" align="right"><font size="1" face="Verdana, Arial, Helvetica"><nobr>   第 6 页（共15 页）</nobr></font></td>
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<font size="2" face="Verdana, Arial, Helvetica">
<p>字符串是 Tcl 中的基本数据类型。<i>string</i> 命令实际上是一组命令，这些命令都是属于 string 的。在使用中，正如在左边的示例中所看到，<i>string</i> 读取的方式非常象来自 OOP 编程特定对象方法的应用程序。</p>
<p>表示信息的 <i>string</i> 命令是 <i>length</i> 和 <i>bytelength</i>（可以有所不同，这取决于字符集）。返回布尔值（1 或 0）的比较是 <i>compare</i>、<i>equal</i> 和 <i>match</i>。这里的模式匹配是由&ldquo;文件名替换&rdquo;（简单类型的匹配通常与外壳操作相关）完成。还可以通过独特的 regex 和 regsub 命令来使用&ldquo;高级正规表达式&rdquo;。</p>
<p>在 Tcl 中执行 <i>index</i>、<i>last</i>、<i>first</i>、<i>wordend</i> 和 <i>wordstart</i> 命令可以实现下标功能。字符串修改是由 <i>tolower</i>、<i>toupper</i>、<i>totitle</i>、<i>trim</i>、<i>trimleft</i>、<i>trimright</i>、<i>replace</i> 和 <i>map</i> 来处理的。后者需要预先定义一个字符映射表。用 <i>range</i> 抽取子字符串，用 <i>repeat</i> 多次输出字符串。</p>
<p>可以使用 <i>append</i> 命令，将文本添加到现有变量中。通过使用与 C 语言的 printf 命令相同的样式和约定，<i>format</i> 命令可用来生成输出字符串。<i>scan</i> 对字符串进行解析并将值赋值给变量。最后，从 Tcl 8.0 开始，用 <i>binary format</i> 和 <i>binary	scan</i> 命令添加了将二进制数据作为字符串处理的功能（因而能够处理空字符，而不会失败）。</p>
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