<HTML> <HEAD> <!-- This HTML file has been created by texi2html 1.51 from ProgrammersManual.texinfo on 4 March 1997 --> <TITLE>LambdaMOO Programmer's Manual - Subsequences</TITLE> </HEAD> <BODY> Go to the <A HREF="ProgrammersManual_1.html">first</A>, <A HREF="ProgrammersManual_19.html">previous</A>, <A HREF="ProgrammersManual_21.html">next</A>, <A HREF="ProgrammersManual_77.html">last</A> section, <A HREF="ProgrammersManual_toc.html">table of contents</A>. <P><HR><P> <H4><A NAME="SEC20" HREF="ProgrammersManual_toc.html#TOC20">Extracting a Subsequence of a List or String</A></H4> <P> The range expression extracts a specified subsequence from a list or string: </P> <PRE> <VAR>expression-1</VAR>[<VAR>expression-2</VAR>..<VAR>expression-3</VAR>] </PRE> <P> The three expressions are evaluated in order. <VAR>Expression-1</VAR> must return a list or string (the <STRONG>sequence</STRONG>) and the other two expressions must return integers (the <STRONG>low</STRONG> and <STRONG>high</STRONG> indices, respectively); otherwise, <CODE>E_TYPE</CODE> is raised. The <CODE>$</CODE> expression can be used in either or both of <VAR>expression-2</VAR> and <VAR>expression-3</VAR> just as before, meaning the length of the value of <VAR>expression-1</VAR>. </P> <P> If the low index is greater than the high index, then the empty string or list is returned, depending on whether the sequence is a string or a list. Otherwise, both indices must be between 1 and the length of the sequence; <CODE>E_RANGE</CODE> is raised if they are not. A new list or string is returned that contains just the elements of the sequence with indices between the low and high bounds. </P> <PRE> "foobar"[2..$] => "oobar" "foobar"[3..3] => "o" "foobar"[17..12] => "" {"one", "two", "three"}[$ - 1..$] => {"two", "three"} {"one", "two", "three"}[3..3] => {"three"} {"one", "two", "three"}[17..12] => {} </PRE> <P><HR><P> Go to the <A HREF="ProgrammersManual_1.html">first</A>, <A HREF="ProgrammersManual_19.html">previous</A>, <A HREF="ProgrammersManual_21.html">next</A>, <A HREF="ProgrammersManual_77.html">last</A> section, <A HREF="ProgrammersManual_toc.html">table of contents</A>. </BODY> </HTML>