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<h3 class="section">5.1 Escape Sequences in string constants</h3>
<p><a name="index-escape-sequence-notation-283"></a>In double-quoted strings, the backslash character is used to introduce
<dfn>escape sequences</dfn> that represent other characters. For example,
‘<samp><span class="samp">\n</span></samp>’ embeds a newline character in a double-quoted string and
‘<samp><span class="samp">\"</span></samp>’ embeds a double quote character. In single-quoted strings, backslash
is not a special character. Here is an example showing the difference:
<pre class="example"> toascii ("\n")
10
toascii ('\n')
[ 92 110 ]
</pre>
<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.
<dl>
<dt><code>\\</code><dd>Represents a literal backslash, ‘<samp><span class="samp">\</span></samp>’.
<br><dt><code>\"</code><dd>Represents a literal double-quote character, ‘<samp><span class="samp">"</span></samp>’.
<br><dt><code>\'</code><dd>Represents a literal single-quote character, ‘<samp><span class="samp">'</span></samp>’.
<br><dt><code>\0</code><dd>Represents the “nul” character, control-@, ASCII code 0.
<br><dt><code>\a</code><dd>Represents the “alert” character, control-g, ASCII code 7.
<br><dt><code>\b</code><dd>Represents a backspace, control-h, ASCII code 8.
<br><dt><code>\f</code><dd>Represents a formfeed, control-l, ASCII code 12.
<br><dt><code>\n</code><dd>Represents a newline, control-j, ASCII code 10.
<br><dt><code>\r</code><dd>Represents a carriage return, control-m, ASCII code 13.
<br><dt><code>\t</code><dd>Represents a horizontal tab, control-i, ASCII code 9.
<br><dt><code>\v</code><dd>Represents a vertical tab, control-k, ASCII code 11.
<!-- We don't do octal or hex this way yet. -->
<!-- @item \@var{nnn} -->
<!-- Represents the octal value @var{nnn}, where @var{nnn} are one to three -->
<!-- digits between 0 and 7. For example, the code for the ASCII ESC -->
<!-- (escape) character is @samp{\033}.@refill -->
<!-- @item \x@var{hh}@dots{} -->
<!-- Represents the hexadecimal value @var{hh}, where @var{hh} are hexadecimal -->
<!-- digits (@samp{0} through @samp{9} and either @samp{A} through @samp{F} or -->
<!-- @samp{a} through @samp{f}). Like the same construct in @sc{ansi} C, -->
<!-- the escape -->
<!-- sequence continues until the first non-hexadecimal digit is seen. However, -->
<!-- using more than two hexadecimal digits produces undefined results. (The -->
<!-- @samp{\x} escape sequence is not allowed in @sc{posix} @code{awk}.)@refill -->
</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,
<pre class="example"> 'I can''t escape'
I can't escape
</pre>
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