<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ --> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Escape Sequences in String Constants (GNU Octave (version 5.1.0))</title> <meta name="description" content="Escape Sequences in String Constants (GNU Octave (version 5.1.0))"> <meta name="keywords" content="Escape Sequences in String Constants (GNU Octave (version 5.1.0))"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="makeinfo"> <link href="index.html#Top" rel="start" title="Top"> <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="Strings.html#Strings" rel="up" title="Strings"> <link href="Character-Arrays.html#Character-Arrays" rel="next" title="Character Arrays"> <link href="Strings.html#Strings" rel="prev" title="Strings"> <style type="text/css"> <!-- a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} blockquote.smallquotation {font-size: smaller} div.display {margin-left: 3.2em} div.example {margin-left: 3.2em} div.lisp {margin-left: 3.2em} div.smalldisplay {margin-left: 3.2em} div.smallexample {margin-left: 3.2em} div.smalllisp {margin-left: 3.2em} kbd {font-style: oblique} pre.display {font-family: inherit} pre.format {font-family: inherit} pre.menu-comment {font-family: serif} pre.menu-preformatted {font-family: serif} pre.smalldisplay {font-family: inherit; font-size: smaller} pre.smallexample {font-size: smaller} pre.smallformat {font-family: inherit; font-size: smaller} pre.smalllisp {font-size: smaller} span.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} ul.no-bullet {list-style: none} --> </style> <link rel="stylesheet" type="text/css" href="octave.css"> </head> <body lang="en"> <a name="Escape-Sequences-in-String-Constants"></a> <div class="header"> <p> Next: <a href="Character-Arrays.html#Character-Arrays" accesskey="n" rel="next">Character Arrays</a>, Up: <a href="Strings.html#Strings" accesskey="u" rel="up">Strings</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> <hr> <a name="Escape-Sequences-in-String-Constants-1"></a> <h3 class="section">5.1 Escape Sequences in String Constants</h3> <a name="index-escape-sequence-notation"></a> <p>In double-quoted strings, the backslash character is used to introduce <em>escape sequences</em> that represent other characters. For example, ‘<samp>\n</samp>’ embeds a newline character in a double-quoted string and ‘<samp>\"</samp>’ embeds a double quote character. In single-quoted strings, backslash is not a special character. Here is an example showing the difference: </p> <div class="example"> <pre class="example">double ("\n") ⇒ 10 double ('\n') ⇒ [ 92 110 ] </pre></div> <p>Here is a table of all the escape sequences used in Octave (within double quoted strings). They are the same as those used in the C programming language. </p> <dl compact="compact"> <dt><code>\\</code></dt> <dd><p>Represents a literal backslash, ‘<samp>\</samp>’. </p> </dd> <dt><code>\"</code></dt> <dd><p>Represents a literal double-quote character, ‘<samp>"</samp>’. </p> </dd> <dt><code>\'</code></dt> <dd><p>Represents a literal single-quote character, ‘<samp>'</samp>’. </p> </dd> <dt><code>\0</code></dt> <dd><p>Represents the null character, control-@, ASCII code 0. </p> </dd> <dt><code>\a</code></dt> <dd><p>Represents the “alert” character, control-g, ASCII code 7. </p> </dd> <dt><code>\b</code></dt> <dd><p>Represents a backspace, control-h, ASCII code 8. </p> </dd> <dt><code>\f</code></dt> <dd><p>Represents a formfeed, control-l, ASCII code 12. </p> </dd> <dt><code>\n</code></dt> <dd><p>Represents a newline, control-j, ASCII code 10. </p> </dd> <dt><code>\r</code></dt> <dd><p>Represents a carriage return, control-m, ASCII code 13. </p> </dd> <dt><code>\t</code></dt> <dd><p>Represents a horizontal tab, control-i, ASCII code 9. </p> </dd> <dt><code>\v</code></dt> <dd><p>Represents a vertical tab, control-k, ASCII code 11. </p> </dd> <dt><code>\<var>nnn</var></code></dt> <dd><p>Represents the octal value <var>nnn</var>, where <var>nnn</var> are one to three digits between 0 and 7. For example, the code for the ASCII ESC (escape) character is ‘<samp>\033</samp>’. </p> </dd> <dt><code>\x<var>hh</var>…</code></dt> <dd><p>Represents the hexadecimal value <var>hh</var>, where <var>hh</var> are hexadecimal digits (‘<samp>0</samp>’ through ‘<samp>9</samp>’ and either ‘<samp>A</samp>’ through ‘<samp>F</samp>’ or ‘<samp>a</samp>’ through ‘<samp>f</samp>’). Like the same construct in <small>ANSI</small> C, the escape sequence continues until the first non-hexadecimal digit is seen. However, using more than two hexadecimal digits produces undefined results. </p></dd> </dl> <p>In a single-quoted string there is only one escape sequence: you may insert a single quote character using two single quote characters in succession. For example, </p> <div class="example"> <pre class="example">'I can''t escape' ⇒ I can't escape </pre></div> <p>In scripts the two different string types can be distinguished if necessary by using <code>is_dq_string</code> and <code>is_sq_string</code>. </p> <a name="XREFis_005fdq_005fstring"></a><dl> <dt><a name="index-is_005fdq_005fstring"></a><em></em> <strong>is_dq_string</strong> <em>(<var>x</var>)</em></dt> <dd><p>Return true if <var>x</var> is a double-quoted character string. </p> <p><strong>See also:</strong> <a href="#XREFis_005fsq_005fstring">is_sq_string</a>, <a href="Character-Arrays.html#XREFischar">ischar</a>. </p></dd></dl> <a name="XREFis_005fsq_005fstring"></a><dl> <dt><a name="index-is_005fsq_005fstring"></a><em></em> <strong>is_sq_string</strong> <em>(<var>x</var>)</em></dt> <dd><p>Return true if <var>x</var> is a single-quoted character string. </p> <p><strong>See also:</strong> <a href="#XREFis_005fdq_005fstring">is_dq_string</a>, <a href="Character-Arrays.html#XREFischar">ischar</a>. </p></dd></dl> <hr> <div class="header"> <p> Next: <a href="Character-Arrays.html#Character-Arrays" accesskey="n" rel="next">Character Arrays</a>, Up: <a href="Strings.html#Strings" accesskey="u" rel="up">Strings</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> </body> </html>